Delayed SMS delivery can have several different reasons.
There might be an issue with the recipient phone itself. If the phone is switched off, in roaming or out of network coverage, we will try to re-deliver the message for up to several days. The exact timespan varies, with most networks trying to deliver a message for 48-72 hours. If you have set a validity period on your SMS we will retry during this period only.
It is also possible that the delay was caused by a loss of connection between the phone and the network. A restart of the phone re-establishes the connection and allows the SMS to be delivered.
If you encounter this issue more often or see that this is affecting multiple numbers, we can investigate this in more detail. To do so, the following information is needed from your side:
- At least three and ideally ten affected recipient numbers (the more examples the easier for us to investigate)
- Date and timestamps (including time zone) when the messages were sent and when they were delivered on the phone.