[Matt]

This is a network hangup and likely nothing wrong with your phone.

Voice calls always take priority over SMS, so if your on a tower area that is busy, it is possible they are getting delays due to an overload on the towers with voice calls. It is also possible that something in the routing of your message is being held up.

It is well known that setting your phone to Sprint Only (as a tech mentioned to your on the phone) will sometimes help with this. The reasoning is a lot of times with it set to Automatic, your phone might be switching between towers too often and a message may not come through until you are toggled back to a Sprint tower.

That being said, coverage or overload isn't always the issue. Sometimes if it is happening a ton and in multiple different areas, it could be a routing issue on Sprint's end. Likely, they will make a network ticket to attempt to resolve this. These typically take a few days to hear back from. If you are experiencing this everywhere and it is happening almost all the time, perhaps it would be wise to call Technical Support (do not talk to ordinary care) and tell them a store tech told them you needed to open up a ticket. They will likely still go through some various troubleshooting, but eventually will make said ticket. Then you wait a few days and will get a confirmation call or email letting you know the issue is hopefully resolved.

Finally, it sometimes can be a defective phone. An corp sprint Service & Repair store can test your device to make sure it is sending/receiving signal correctly. It is a very simple test done in an isolation box that only takes a few minutes.

Hopefully this information is helpful to you (or anyone)