Delay - A delay in SMS can be caused by numerous factors, it can be caused by the end handset, a delay between your system and the network, a delay with a carrier etc. To troubleshoot this further it's worth checking if this is isolated to specific handsets or handset networks, SMS the number directly if possible, is it received in the same timeframe, is the handset perhaps out of range and not receiving the messages.
You can also pull an API export (or view in the platform) messages sent and have a look at the 'Submitted/Delivered' times, are all users having an issue or just specific numbers/handsets, 90% of the time it will be the handset or the handset carrier network causing the delay.
Not Received (Sending) - If your messages aren't sending then this could be from a number of factors, if you have setup a new service with us, revert back to the provisioning team for further assistance. If this is a pre-existing service then it may depend on how you are sending out. For all types the first step you can do is to pull an SMS report (or check in the platform) and make sure your SMS' are going into the system, then check the delivered time/date column. If you don't see your SMS in the report or in the platform this signifies a link issue between your system and the network.
If you send via the API, check if you received any errors for messages you have sent, try sending to the same number (is there still an error?) Email to SMS and SMPP you will need to contact us to ensure we received the request but in the case of SMPP there may not be many logs kept for failures of connectivity. It's best in such cases to implement true delivery receipts and to setup an automated retry with exponential back-off in such cases.
Not Received (Receiving) - If you aren't receiving messages as intended the first place to check is the platform, regardless of where messages are sent back to (in the case of SMPP or Email), replies should be viewable in the platform. Login and check for them, if you are unable to see replies you can try sending some tests from different networks to the relevant number and ensure there is no issues there. The next step would be to get in touch with us so we can troubleshoot.
Unable to View - If you are sending and receiving okay but you aren't able to view SMS' in API reports or in the platform, reach out to us but ensure the SMS you are searching for isn't just on a separate page for that day.
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