Top Reasons Your SMS Isn’t Being Delivered


Text messaging introduced into the daily practice of most businesses and individuals saves time and costs on communication and provides efficient service delivery

With the impressive figure of 560 billion SMS being sent every month, some minor occasional issues with delivering messages might come as no surprise but there are the top factors that you need to know as they could strongly signal of decreasing the guarantee of SMS delivery.

What makes messages fail to deliver

  • Invalid numbers

Although obvious, sending SMS to the invalid number stays the top reason for the failure of message delivery. In case of detecting the recipients’ invalid numbers, the senders will be notified of SMS error similarly to being notified of error upon delivery to the invalid email address. Checking on entering the correct number as well as confirming its validity might be the issue solution.

  • Interference of poorly coded applications

In some cases, a failure of SMS delivery can be caused by poorly coded applications interfering with the operating system of the mobile phone. Restarting the device to the safe mode usually resolves the problem.

  • Network coverage

Messages are highly likely to fail to deliver in locations with the poor network coverage. Generally, weak signal reception is indicated by one or two bars on top of the smartphone display. For the mentioned case, the location with better network coverage improves the situation instantly.

  • The number in roaming

If the number is detected in roaming there might also arise problems with SMS delivery due to various technical issues.

The number in roaming associated with location issues might also cause SMS not being delivered because of restrictions imposed by country policy. For example, in Japan unicode messages are supported upon recognition of Japanese characters in content while for other languages messages may go undelivered or delivered with delay (the overview of SMS features by countries can be found here).

  • Third-party applications

Too many third-party applications can also create a conflict with the sender/recipient’s messaging app, so switching to a safe mode is advisable.

  • Mobile device issues

The unresolved issues with app data may also result in failing prompt SMS delivery. If temporary files or cache get corrupted it makes a bad impact on the performance of a messaging app and SMS delivery.

If the sender/recipient’s inbox is overloaded, it might run out of space, which decreases the quality of messaging app operation when it comes to sending and delivering the texts.

  • Carrier restrictions

One of the top reasons for SMS delivery failure is spam filters detected by carrier algorithms that block the texts prior to being delivered. Regretfully, the mentioned filters are somewhat randomly chosen and determined by carrier policy.

  • Message filtering

In some other cases, recipients resistant to getting A2P (Application-to-Person) messages reported them to their carrier as a scam so any further marketing messages from that number or the messages containing the content associated with the promotion of products, services or surveying the customers’ experience will be blocked upon sending.

Besides, messages can be marked as ‘spam’ and blocked by carriers for the reason of sending the repetitive links.

Using keywords in the SMS body will be recognized by the carriers as suspicious and might cause blocking the message delivery.

  • Networks difference

For cases when a sender and recipient use different networks, the probability of experiencing failure of SMS delivery is higher than for users of the same network, which is caused by networks and carriers setting their own traffic as a top priority.

  • Heavy network traffic

At times when networks have to adjust to operating under overloaded network traffic conditions, the text delivery might be impacted in a negative way due to congestion of the local networks so the handset users may expect either the delay or even the failure of messages arrival.

As a side note, however good and productive the idea of delivery receipts reports (DLRs) is, unfortunately, it should not be taken as a fail-proof solution for ensuring SMS messages being delivered. Delivery receipts reports can be marked as having a medium or low priority compared with the high priority of delivering the SMS content itself so it might result in a considerable postponement of delivering the reports confirming the message’s arrival in receivers’ accounts.

How to ensure secure SMS delivery

Fixing users’ mobile device issues or configuring network settings for increasing the chances of SMS trouble-free delivery suppose the involvement of multiple parties (senders, carriers, and recipients).

But in most cases, it is enough to apply the right tools eliminating the impact of negative influencing factors to avoid the issues with SMS delivery and ensure that your SMS will not go undelivered.

Messaging that is implemented as a component of marketing and business strategies created the demand for guaranteed deliverability solutions. Nowadays, the market responds to this demand with numerous offers to improve the quality of SMS delivery.

Therefore, applying the software that would reduce the influence of restrictions might come handy indeed, and choosing reliable services that facilitate success of SMS delivery seems the ideal solution.

Let alone the guarantee of receiving your SMS in time, the subscriber would enjoy this service easily overcoming the geo limits in more than 20 countries without the necessity of buying a SIM card. In addition to receiving regular text messages, the user would be able to apply SMS authentication for activating payment systems operations, participation in social networks, and communication in messengers without extra efforts.