Why Isn’t My Message Delivering? 20 Causes and How to Fix Them

You hit send on an important text message. Maybe it’s an appointment reminder, a critical alert, or a time-sensitive customer notification. Then you see it: “Not Delivered.”

Few things are more frustrating than messages that simply disappear into the void. And if you’re running a business that depends on SMS communication, failed deliveries aren’t just annoying. They cost you money, damage customer relationships, and create chaos in your operations.

Here’s the reality: around 1-5% of text messages never reach their intended recipients. For businesses sending hundreds or thousands of messages monthly, that translates to dozens of missed appointments, lost sales, and frustrated customers.

The good news? Most SMS delivery failures have identifiable causes and fixable solutions. This guide walks through the 20 most common reasons why your text messages aren’t delivering, plus proven strategies to achieve delivery rates up to 98%.

What SMS Delivery Actually Means

Before diagnosing why your messages aren’t delivering, it’s important to understand what “delivery” actually means in the SMS world.

Sent vs. Delivered vs. Engaged

When you send a text message, it passes through several stages:

1. Sent: Your message left your device or platform and entered the carrier network
2. Delivered: The message reached the recipient’s phone
3. Engaged: The recipient clicked a link or replied

Just because a message shows as “sent” doesn’t mean it was delivered. Your carrier accepted the message, but it may have been blocked, filtered, or lost somewhere in the network before reaching its destination.

This distinction matters because many delivery failures happen silently. You think your message went through, but it never arrived. Without proper delivery confirmation, you’re left guessing whether your critical communications actually reached your customers.

Common Challenges With SMS Delivery

Businesses face several frustrating challenges when trying to communicate reliably via text message.

Challenge 1: Silent Failures With No Notification

Many SMS platforms don’t tell you when messages fail. Your appointment reminder goes out, you assume it was delivered, and then the patient doesn’t show up. You only discover the delivery failure after the damage is done.

Challenge 2: Carrier Gateway Shutdowns

If you’ve been using carrier email-to-text gateways like @txt.att.net or @vtext.com, your messages likely stopped working entirely in 2025. AT&T shut down their gateway in June 2025, with Verizon and T-Mobile completely dismantling their legacy public gateways by late 2025. Businesses relying on these “free” methods suddenly found themselves without a texting solution.

Challenge 3: Spam Filter False Positives

Legitimate business messages get caught in carrier spam filters daily. You’re trying to send helpful appointment reminders, but the carrier sees a pattern that looks like spam and blocks your messages without warning.

Challenge 4: No Team Visibility

When one person’s phone is responsible for all your business texting, you have no way to know if messages are failing. That single point of failure can silently break your entire communication system.

The good news? These challenges have solutions. Let’s examine the specific causes and how to fix each one.

20 Reasons Why Your Text Messages Aren’t Delivering

Here are the top reasons your texts might not be reaching their destination and what you can do to resolve each issue.

1. Network Connectivity Problems

The most basic cause of failed text delivery is a poor network connection. If your phone shows weak signal bars or no service, your messages may sit in an outbox queue rather than actually transmitting.

Symptoms: Messages stay as “sending” indefinitely, or show a red exclamation mark after attempted send.

How to fix it:

• For mobile phone senders: If you have weak signal bars, messages may sit in your outbox. Try toggling airplane mode to reset your connection.
• For email-to-text senders: If your internet connection drops while sending the email, it never reaches the SMS gateway. Always check your “Sent” folder to ensure the email actually left your outbox.

2. Incorrect Phone Number Format

Sending to an incorrectly formatted phone number guarantees delivery failure. Common mistakes include:

• Missing area codes
• Wrong country codes for international numbers
• Extra digits or spaces
• Transposed numbers

How to fix it: Always verify phone numbers before sending. For business messaging, use a platform that validates numbers automatically and flags invalid entries in your contact list.

3. Sending to Landlines or Non-Text Numbers

Not every phone number can receive text messages. Landlines, most toll-free numbers, and some VoIP numbers aren’t SMS-enabled.

How to fix it: Before bulk messaging, verify that your contact list contains mobile numbers. Some SMS platforms can identify and remove landlines automatically.

4. Recipient’s Phone Is Off or Out of Service

If the recipient’s phone is powered off, in airplane mode, or outside coverage areas, your message can’t be delivered immediately. Depending on the carrier, the message may be held for later delivery or simply dropped.

How to fix it: This is outside your control, but you can mitigate it by:

• Sending messages during normal business hours when phones are typically on
• Setting up automated retry systems for critical messages
• Using a platform that provides delivery status so you know when re-sending is needed

5. Recipient Blocked Your Number

If a recipient has blocked your phone number, your messages will never reach them. You typically won’t receive notification that you’ve been blocked.

Symptoms: Messages show as sent but never delivered. No replies to any messages.

How to fix it: If you suspect you’ve been blocked by a business contact, try reaching out through a different channel (email or phone call) to address any concerns.

6. Recipient Opted Out of Messages

For business messaging, recipients have the right to opt out by texting STOP or similar keywords. Once opted out, you’re legally prohibited from sending them additional messages, and carriers will block delivery attempts.

How to fix it: Respect opt-out requests. If a customer wants to re-subscribe, they must initiate by texting START or a similar keyword. Maintain a clean opt-out list and ensure your messaging platform handles compliance automatically.

7. Recipient Has Billing Issues

If the recipient hasn’t paid their phone bill, their carrier may suspend incoming messages (along with outgoing ones). This is temporary and resolves once they restore their account.

How to fix it: This is outside your control. If you’re having delivery issues with a specific contact who was previously reachable, billing problems may be the cause.

8. Recipient Is Roaming Internationally

When recipients travel internationally, their phone may not be compatible with local networks, or their carrier plan may not include international SMS. Messages sent while roaming often fail silently or experience significant delays.

How to fix it: This is outside your control. If you know a contact is traveling, consider alternative communication methods. For time-sensitive business messages, follow up via email as a backup.

9. Do Not Disturb or Focus Mode Enabled

Modern smartphones have Do Not Disturb (DND) and Focus Mode settings that can silently suppress incoming text notifications. While the message technically delivers, the recipient never sees or hears it arrive. Some DND configurations even delay message delivery entirely until the mode is disabled.

Symptoms: Message shows as delivered on your end, but recipient claims they never received it or saw it hours later.

How to fix it: This is outside your control. For critical business communications, consider:

• Sending during standard business hours when DND is less likely to be active
• Following up via email or phone call for urgent matters
• Using a platform that confirms delivery so you know the message reached the device

10. Device Storage Full

When a recipient’s phone runs out of storage space, it cannot receive new text messages. The device simply has nowhere to store incoming SMS. This is increasingly common as phones fill up with photos, apps, and cached data.

Symptoms: Messages fail to deliver to a specific contact who was previously reachable. Other contacts on the same carrier receive messages normally.

How to fix it: This is outside your control. If you suspect storage issues with a specific contact, try reaching out through an alternative channel. For business messaging, having delivery status visibility helps you identify when individual contacts consistently fail.

11. Carrier Spam Filtering

Carriers aggressively filter messages they suspect are spam. Legitimate business messages often get caught in these filters, especially if they:

• Come from unregistered numbers
• Contain certain keywords or patterns
• Include shortened links from third-party services
• Are sent in high volumes from new numbers
• Contain repeated identical content sent to multiple recipients
• Include email addresses or phone numbers different from the sender
• Use excessive punctuation (!!!) or all-caps text

How to fix it: Use a 10DLC-registered business number for sending. Avoid all-caps text, excessive special characters, and shortened links from generic services. Build sending reputation gradually rather than blasting large volumes immediately. Vary your message content slightly when sending to multiple recipients to avoid triggering “broadcast spam” filters.

12. Carrier Gateway Shutdowns

This is the biggest SMS delivery issue of 2025, and most troubleshooting guides don’t even mention it.

For years, businesses relied on carrier email-to-text gateways like:

• AT&T: @txt.att.net (shut down June 17, 2025)
• Verizon: @vtext.com (shut down August 2025)
• T-Mobile: @tmomail.net (shut down August 2025)

These gateways allowed anyone to send texts by emailing phonenumber@carrier-domain.com. They were free, simple, and worked well enough for basic use. IT departments, healthcare practices, and small businesses relied on them for years.

How to fix it: Switch to a professional email-to-SMS service that uses 10DLC-compliant routing. Platforms like TextBolt preserve your email-based workflow while delivering through carrier-approved channels.

13. Network Outages or Maintenance

Carrier networks occasionally experience outages that prevent message delivery. These are usually temporary but can cause significant disruption during the downtime.

How to fix it: Check your carrier’s status page or social media for reported outages. If there’s an outage, wait for service restoration. For critical business messaging, use a platform that routes through multiple carrier connections to minimize single-carrier outage impact.

14. Network Congestion During Peak Hours

During high-traffic periods like holidays, major events, or natural disasters, carrier networks become congested. Messages may be delayed for hours or dropped entirely as networks prioritize voice calls over SMS.

How to fix it: Avoid sending bulk messages during known high-traffic periods. For time-sensitive communications, use a platform with priority routing. Consider scheduling important messages during off-peak hours when possible.

15. Routing Failures

Messages sometimes get lost in the complex routing between carriers. This is particularly common when:

• Sender and recipient use different carriers
• Messages cross international boundaries
• Network congestion causes timeout failures

How to fix it: Use a business SMS platform with direct carrier connections rather than routing through multiple intermediaries. This reduces the points where messages can get lost.

16. SHAFT Content Violations

The Cellular Telecommunications and Internet Association (CTIA) prohibits messages containing SHAFT content:

• Sex: Adult or sexually explicit content
• Hate: Hate speech or discriminatory content
• Alcohol: Alcohol promotion (with some exceptions)
• Firearms: Gun promotion or sales
• Tobacco: Tobacco/vaping promotion

Messages containing SHAFT content will be blocked by carriers, even from registered business numbers.

How to fix it: Review your message content for anything that could be flagged. If your business involves regulated industries (alcohol, cannabis), work with a carrier-approved messaging provider that specializes in compliant messaging for those verticals.

17. Suspicious Links or URL Shorteners

Carriers have learned that shortened URLs from services like bit.ly are frequently used in phishing and spam campaigns. Including these links in your messages significantly increases the chance of carrier blocking.

How to fix it:

• Use your own branded short domain for links
• Include full URLs when possible
• Avoid multiple links in a single message
• Don’t use free URL shorteners

18. Message Too Long (Splitting Issues)

Standard SMS messages are limited to 160 characters. Longer messages are split into multiple segments and reassembled on the recipient’s phone. Sometimes this process fails, resulting in:

• Missing message segments
• Segments arriving out of order
• Garbled or incomplete messages

Using special characters or emojis reduces the limit to 70 characters per segment due to Unicode encoding.

How to fix it: Keep messages concise when possible. If you must send longer messages, use a platform that handles segmentation properly. Learn more about SMS character limits to optimize your messages.

19. Lack of 10DLC Registration

10DLC (10-Digit Long Code) registration is now required for businesses sending text messages in the United States. Unregistered numbers face:

• Aggressive carrier filtering
• Lower message throughput limits
• Higher delivery failure rates
• Risk of complete number blocking

How to fix it: Register your business and messaging campaigns through The Campaign Registry (TCR). Many professional SMS platforms, including TextBolt, handle this registration automatically as part of onboarding.

20. Long Code Throttling and Volume Limits

If you’re using personal phone numbers, email gateways, or unregistered long codes for business messaging, you’ll hit strict throttling limits. Carriers restrict these numbers to approximately 1 message per second and 200-500 messages per day. Exceed these limits and your number gets temporarily or permanently blocked.

How to fix it: Switch to a professional SMS platform that uses 10DLC-registered numbers or toll-free numbers. These have much higher throughput limits (thousands of messages per day) and don’t face the same throttling restrictions as personal numbers or legacy email gateways.

How to Ensure Your Messages Get Delivered

Now that you understand why messages fail, here’s how to maximize your delivery rates.

Use a 10DLC-Compliant Platform

Sending from a 10DLC-registered number is the single most important factor for business SMS delivery. Registered numbers receive:

• Higher carrier trust scores
• Better throughput limits
• Fewer spam filter blocks
• Delivery confirmation

Verify Your Contact List

Invalid numbers waste credits and hurt your sending reputation. Regularly:

• Remove numbers that consistently fail
• Validate new numbers before adding to campaigns
• Flag and investigate contacts with repeated delivery failures
• Sync with your existing contacts rather than manually entering numbers

Follow SHAFT Guidelines

Even legitimate business messages can get filtered if they contain trigger words or patterns. Review every message for:

• Prohibited content categories
• Aggressive sales language
• All-caps text
• Excessive punctuation
• URL shorteners

Monitor Delivery Reports

You can’t fix what you can’t see. Use a platform that provides:

• Real-time delivery status
• Failed message alerts
• Delivery rate analytics
• Individual message tracking

Use Email-to-SMS for Reliability

Email-to-SMS platforms like TextBolt combine the simplicity of sending from your inbox with the reliability of carrier-approved routing. You get the ability to send a text message from your computer along with:

• Familiar workflow (no new software to learn)
• 10DLC compliance handled automatically
• Delivery confirmation in your email
• Complete audit trail

The TextBolt Solution: Up to 98% Delivery Rate

TextBolt was built specifically to solve the SMS delivery problems businesses face today.

How TextBolt Achieves High Deliverability:

1. 10DLC registration included: Every TextBolt account goes through business verification and 10DLC registration. Carriers trust TextBolt messages.
2. Carrier approved routing: Messages travel through verified business channels, not the deprecated carrier gateways that get blocked as spam.
3. Dedicated business numbers: Your messages come from your professional toll-free number, not a random carrier address.
4. Delivery confirmation: Every message is tracked. You know immediately if something fails, and you can see the status right in your email inbox.
5. Team access: Multiple team members can send messages from the same business number. No single point of failure means no silent delivery breakdowns.

How It Works:

1. Install the TextBolt Gmail add-on or send from any email client
2. Complete business verification (takes about 30 minutes)
3. Send texts by emailing phonenumber@sendemailtotext.com
4. TextBolt delivers through carrier-approved routes with up to 98% delivery rates
5. Replies come back to your email inbox

If you’ve been struggling with “Not Delivered” messages, carrier gateway failures, or spam filter blocks, TextBolt provides the reliable alternative businesses need. See our pricing to find the plan that fits your messaging volume.