Wifi calling issues, suddenly with AT&T

Hi all. On my six S plus, I enabled wifi calling as our cell coverage isn't great. Yesterday out of nowhere, I noticed my bars said LTE. Thinking nothing, I reconected. This morning I had a good chat with a friend. Just a few minutes ago, my Mac told me, something along the lines of wifi calling can't be enabled on this account, contact carrier. I just updated to IOS 10.3 and would really like to not have to call if I don't have too. I reset network settings, I also reset the phone with home and power. I didn't turn it off and back on as that did the same thing, even turned off then on, wifi calling. Any help would be great. thanks. btw, I mean the IOS 30.3.2 or whatever the mini update was.

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#1 AT&T and Wi-Fi calling

Hello Siobhan, this is what before having to do to get their Wi-Fi calling enabled for AT&T. So you can have no choice but to call and get your account updated. Yeah I know it possibly be a pain in the butt but it's what has to happen. Luckily for me with T-Mobile I did not have to do that. I wish this was the case for AT&T but it's not.

#2 Restored my iPhone

Tried to reset my iPhone then restored it. the account owner is fine, it's just me. I might switch the sim card tomorrow. thanks for the help, it was just random it stopped working.

#3 It works some of the time

Hi. So I restored, turned off, then on, wifi calling no dice. I connected to my 2.4 ghz network, works fine. It has the same pw as my five gig so I don't know. Maybe a reset of the router will work. Or check it's firmware.

#4 AT&T and Wi-Fi calling

Five minutes phone call to AT&T is not cannot harm you. As it is what needs to be done. As resetting your network is not cannot resolve the issue. As you're able to Connect to your network. And do other things I'm assuming correct?