My wife and I purchased unlocked versions of this phone directly from Samsung in November 2020. We have only used them on PureTalk's (AT&T's) network. I have noticed intermittent connectivity issues more with my wife's phone than mine. Usually would start with not being able to send/receive MMS. Power cycling did not help. Finally I reached out to the carrier. I tried several tings they suggested: Reset Network Connections; pull SIM out and then replace; Configure a new APN; etc. Initially resetting the network settings would work, but she would have to do it about once every 5 days. Yesterday it quit connecting and nothing has worked. And now my phone is doing the same thing. Has anyone else had this problem?