I have a S21 Plus, about 3 months old. Whether I use the default messaging app or Textra, every few days it will stop receiving text messages. They show as not downloaded. Tapping on them will not download them. I have to reboot my phone for them to come through. Everything else will be working and I can access calls and the Internet. But I have to get this solved as at times there will be several messages not received. Thoughts?
your device may be experiencing difficulty connecting and staying connected to the network. I would check with the carrier first to see if they can help.
Additionally try Network Reset on your device. If the issue persist then submit error report to Samsung Members after you notice the issue again. Doing so will allow logs to be collected and analyzed by the techs to help identify the cause.
If you don't mind, could you share your device's model number, software version and the carrier you are with?