Non-delivery means we were unable to deliver the message. There may be multiple reasons for failure to deliver, examples being:
| Issue | Explanation |
| The number format is not correct | All numbers need to be added in the international format. For more information see here: Numbers format. |
| The phone was switched off | Make sure the mobile number you enter is available and valid so that you do not waste your credit unit on messages sent to unachievable phone numbers. |
| The network did not enable receiving SMS for this subscriber (e.g. due to low balance, or a do-not-disturb (DND) list for SMS services) | |
| The phone was out of network coverage | Most connection problems are resolved simply by restarting the phone because the connection to the network is refreshed. |
| There was an error in the Application to Person (A2P) SMS connection between the phone and the network. For further information, please see below (Difference between A2P and P2P) | |
| The number is in roaming (outside of the home country) | We can not guarantee delivery for roaming numbers. This depends on the agreements that we can conclude between the home network and the roaming network. |
| The messages were not delivered due to local restrictions. | Many countries and networks have restrictions regarding SMS content and senders. For detailed information per country, please see Country Info & Restrictions. |