Quick heads up to those US ATT users out there. ATT currently has a provisioning bug where some SIM cards will NOT re-provision on the ATT network upon your return to the states if the sim card had not been used for some indeterminate length of time. The only fix is to get a new SIM card. I spent multiple chats with customer support and finally they admitted they are having problems when some SIM cards are off the network for a undetermined amount of time. The new sim cards are supposedly OK. Anyhow... I would suggest if you take out your ATT sim to put it in once a week or so when abroad. If you don't it just may require replacement. Yes, you can get on open networks, but you still can't make voice calls sms etc.
[xxxxx] : I have confirmed with our network team that people are facing issue with services on their old sim who have returned from abroad. This is happening due to provisioning issue and we are trying to reprovision and as an alternate option helping with replacement.
TLDR : Answer Summary
AT&T users may experience provisioning issues with their SIM cards if they have been inactive for an extended period while abroad. This can lead to difficulties re-establishing service upon returning to the U.S., with the only solution being to replace the SIM card. Users are advised to activate their SIM cards periodically while overseas to avoid this problem.
