Why Text Message Failed to Send: 16 Common Reasons & How to Resolve

SMS messages have a 98% open rate. This fact alone is enough to put SMS marketing on par with mobile app marketing in terms of customer engagement and retention, and push a lot of businesses to use SMS as a major customer communication channel.

Yet, even well-crafted SMS campaigns will inevitably fail if message delivery rates are subpar. Despite being a common problem in SMS marketing, failed messages are more than an unpleasant issue – they can cost your business significant lost revenue.

The good news is that the “message not delivered” problem is solvable. Below, we’ll explain the reasons for text message failure and how to fix them to maximize your SMS marketing efficiency.

Why Text Message Failed to Send: 16 Most Common Reasons [with Solutions]

Text messages are yet another communication channel that can help you build and maintain strong connections with customers, keeping them interested and engaged and eventually driving them toward conversions. Companies that include SMS in their omnichannel strategies boost customer engagement by over 47% and enjoy the ROI of up to $41 per dollar spent on SMS marketing.

With that in mind, non-delivered text messages feel even more painful, especially when you don’t know what’s going wrong. There is more than one possible reason behind the ubiquitous message send failure. However, forewarned is forearmed. Let’s examine the most common reasons for the “Message was not delivered” error in more detail. 

1. Invalid or deactivated phone numbers

A simple typo, wrong or missing digit, incorrect country code, and invalid recipient number cause text message delivery problems more often than you think. Customers switch carriers, change phone numbers, and deactivate old phones. In other words, the number may simply no longer exist. Not taking this into account inevitably results in wasted message credits and low delivery rates.

How to resolve: 

• Keep your contact lists fresh and verified. Special SMS validation and list-cleaner tools can automatically identify and mark invalid or inactive numbers. 
• Encourage customers to update their data in your messages, forms, or emails to maintain an active database.

2. Carrier limitations

Mobile carriers have strict rules and text message filters in place to shield users from spam, scams, and message overload. Using excessive promotional language like “FREE,” “Click NOW,” or “LIMITED TIME OFFER” can trigger blocks. Besides, some mobile companies limit the number of recipients for bulk texting, especially if you use a non-registered number.

How to resolve: 

• Avoid phrases and formatting styles associated with spam. Refrain from using caps, abundant punctuation, and sales phrases that sound pushy.
• Rely on opt-in lists to send SMS only to those who have agreed to receive them to keep in line with TCPA or GDPR rules. 
• Register a dedicated sender ID to stand out as a credible, legitimate business to the mobile carrier you’re using. 

3. Restricted content in the text message

Using spammy wording triggers can get your number blocked, but certain types of content can lead to message send failure as well. Unlawful, harmful, deceptive, or offensive materials are considered prohibited content and should not be used in marketing campaigns. Forbidden topics include:

• Drugs, alcohol, tobacco, or gambling.
• Adult content.
• Questionable financial offers and phishing.
• Discriminatory or offensive language.

How to resolve:

• Proofread your messages to ensure they don’t sound dubious, robotic, or unnatural.
• Stick to the user guidelines set forth by the carrier or your messaging platform. 
• Don’t send offers, claims, or requests that may be treated as improper or infringing. 

4. Suspicious links

Mobile carriers are extremely cautious when it comes to links in text messages, as these are often used in scams. Providers flag and block suspicious URLs, leaving your SMS no chance to reach its destination. If you notice a lot of “Message was not delivered” results in your uplink response, this might be the case.

How to resolve:

• Use trusted link shortener services or platforms, preferably those directly integrated with your SMS marketing service.
• Use a verified domain associated with your brand or clearly showing your brand name. 
• Don’t include multiple links in a single message. 

5. Excessive messaging

Mobile operators and SMS gateways tend to limit the message flow per second or per minute to avoid network overload and reduce spam. Exceeding these thresholds will cause text message failure.

How to resolve:

• Use message throttling to spread your sends evenly. 
• Schedule your messages in batches for steady delivery to different customer groups. 
• Divide your audience into smaller segments based on customer behavior or location, which will also improve personalization. 

6. Sender ID blocking

Before winning customer trust and loyalty, you must first convince your mobile carrier that you are a trusted sender. Thus, if your user ID is not registered and verified by the carrier or your sender details match a blacklisted number, you’ll end up with a “Text message failed to send” error.

How to resolve:

• Always register your sender ID with your SMS service provider directly. This could be a company name or 10DLC (10-digit long code).
• Comply with network and regional requirements for sender data authentication.

6. Wrong message type

When you try to use a personal number for mass texting, you’ll get into a P2P vs. A2P messaging conflict and experience delivery failures. P2P (person-to-person) routes are used for individual communication, while A2P (application-to-person) is a distinct route for businesses to send bulk text messages.

How to resolve:

• Use a registered SMS service for proper routing.
• Use an appropriate delivery method for your message type (some regions restrict MMS).
• Employ short code numbers for high-volume sends.

7. DND (Do Not Disturb) list restrictions

If your recipients enable Do Not Disturb (DND) settings on their phones or have their numbers on an official DND list, you’ll get a text message error even if your texts are legitimate and well-composed.

How to resolve:

• Set appropriate routes for promotional vs. transactional messages to deliver critical text messages if your customers are on the DND list. 
• Review local DND regulations and make sure you have all permissions before starting your SMS campaign.

8. Encoding and format mismatch

A message may be blocked because it is encoded incorrectly, contains unsupported characters, or exceeds text limits. For example, the GSM format supports SMS up to 160 characters while limiting some symbols and emojis. Unicode, on the other hand, allows Arabic, Chinese, and Cyrillic scripts if the text doesn’t exceed 70 characters. The system automatically switches encodings to accommodate your texts, which can lead to incomplete or undelivered messages.

How to resolve:

• Align encoding with your carrier and regional standards.
• Adhere to SMS character limits.
• Avoid unsupported or hidden characters.

9. Recipient-enabled limitations

When a user unsubscribes from your send list, blocks your number, or refuses to receive your messages, a mobile operator activates automatic filters that will reject further SMS from you.

How to resolve:

• Respect your customers’ decisions and confirm opt-outs.
• Maintain contact list hygiene and remove unsubscribed or inactive contacts from your sending lists.

10. Insufficient account balance

It might seem like a trivial reason for text message failure, but an empty SMS platform account or a terminated mobile plan can stop your campaign in its tracks. 

How to resolve:

• Before launching a new campaign or sending bulk messages, check your balance.
• Set up automatic top-ups so you don't lose customers when your balance falls below an established threshold.

11. The recipient device is beyond reach 

A recipient can turn off their phone, activate airplane mode when traveling, or live in a location with patchy signal coverage. On top of that, some countries restrict roaming for foreign users, while a person can also deactivate roaming when abroad.

How to resolve:

• Activate automatic retries to resend the text message if the first delivery fails. 
• Employ message queuing to keep undelivered messages in line.
• Maintain alternative channels such as email, push notifications, iMessage, and instant messaging apps.

12. Carrier service problems

Carrier service disruptions might happen due to large-scale issues in the mobile network, such as:

• Network outages during peak times, emergency events, or busy seasons.
• Technical errors, internal glitches, or routing misconfigurations. 
• System updates and maintenance work.
• Regional outages caused by weather conditions or infrastructural damage. 

Possible solutions:

•  Use omnichannel communication combining tools like messengers, in-app messages, and push notifications. 
• Set automatic fallback options to reroute your messages if SMS delivery fails.

13. SMS function deactivated

Another possible reason behind a message send failure is that your recipient has disabled SMS on their phone. Some people turn this function off manually, or it might accidentally switch it off after a software update or a system reset. 

Possible solutions:

• Encourage recipients to verify SMS settings when they subscribe to your services.
• Maintain several communication channels to reach users who are uncontactable via SMS.

14. Network congestion

When message volume exceeds the mobile network's carrying capacity, it causes an overload and “text message failed to send” issues. SMS delays, queuing, or failures can occur due to local network problems at public events or excessive SMS traffic during evening hours, weekends, or holidays.

Possible solutions:

• Partner with an SMS service provider that uses multiple carrier routes for better load distribution. 
• Optimize your sending schedule to avoid peak hours. 
• Use message throttling to slow down your sending.

15. International messaging restrictions

Some countries have strict messaging laws and policies that set technical and regulatory barriers to message delivery from abroad. Restrictions can affect:

• Message content.
• User ID registration.
• Messaging route compatibility.
• SMS sending times.
• User data protection and privacy laws.

Possible solutions:

• Monitor and follow country-specific messaging regulations and standards.
• Work with SMS service providers that have solid relationships with local carriers and know about their limitations. 

How to Prevent “Text Message Failed to Send” Issue

Just as a structured, consistent approach is crucial for mobile app branding and laying a strong foundation for further marketing efforts, a well-thought-out approach to SMS campaigns will help you get the most out of this tool. Here are the best practices to improve your delivery rates and increase your campaign efficiency. 

Keep your contact list up-to-date and verified

The success of any SMS campaign hinges on its contact list. Sending text messages to invalid or outdated phone numbers is not only a waste of time and effort but also of your marketing budget. That’s where a simple number validation can become a game-changer by ensuring that all numbers on your list are active, correctly formatted, and can receive texts. 

Maintain proper opt-in and compliance

Perform bulk sends responsibly. Your audience should agree to receive your text messages. With a proper opt-in process, you’ll demonstrate regulatory compliance and strengthen your sender reputation. 

Optimize message content and formatting

Keep your messages within the standard SMS character limit. Steer clear of spammy words or phrases and banned content that may raise suspicions or even cause system blocks. Use verified and trusted links or a reputable link shortener tied to your domain.

Choose a reliable SMS gateway provider

With the right partner, you can rest assured that your text messages are routed efficiently, handled by reputable carriers, and supported with real-time delivery tracking. Your choice of provider can mean the difference between instant delivery and message send failure. 

Segment and schedule smartly

Optimize timing and targeting. Throttle your messages and segment your audience wisely to control delivery speed and improve relevance. Set up your campaigns based on time zones, audience behavior, and message type.

Track delivery reports and analytics

Mass sends require monitoring and control. Keep an eye on your delivery statuses and bounce rates. Analyze failed messages to spot recurring issues and eliminate them before they grow into bigger problems and hurt your marketing efficiency. 

Consistently review and tailor your campaign strategy

Mobile network infrastructure, standards, carrier rules, and user habits can change over time. So, SMS marketing is not a one-and-done task, but rather a strategy that requires supervision and iteration to be effective.

Track your campaign performance and revise your message templates, timing, and targeting when necessary. Test new approaches and refine your processes to catch up with regulatory and other changes. 

How to Successfully Send Text Messages with Reteno

Creating an efficient SMS campaign is easier said than done unless you have the right partner like Reteno by your side. As an omnichannel messaging platform, Reteno can help you maximize user engagement, drive retention, and boost conversions by setting up efficient customer communication across 8 different channels or combining them in a multichannel marketing strategy.

When it comes to SMS messages, our platform will do all the hard work for you: create perfectly personalized campaigns, segment your audience, automate sends, analyze campaign results, and ensure complete regulatory compliance across regions. All you have to do is just reap the benefits of a professionally set SMS campaign.

Conclusion

Preparation, a solid strategy, and the right tools are crucial to successful SMS campaigns. By using best practices in a combo with a robust platform, you can turn your SMS campaigns from a hit-or-miss effort into a reliable, high-impact channel for business communication and customer engagement.