iPhone 7 Plus will not make or receive calls - Call Fail message

My iPhone won't let me make or receive calls after software 13.7. My Carrier is AT&T. I spent an hour with them and nothing is wrong on the network. I put my sim card in another device and it worked fine.

Is there anyway to fix this. I can receive voicemails but when I swipe to answer it says Call Fail. Some callers are reporting that it says call fail for them as well. When I make calls it ring and then show call fail.

Here are all the steps I have tried to no avail:

Check your iPhone settings

1. Turn Airplane Mode on and off. Go to Settings and turn on Airplane Mode, wait five seconds, then turn it off.
2. Check your Do Not Disturb settings. Go to Settings > Do Not Disturb and make sure it's off.
3. Check for any blocked phone numbers. Go to Settings > Phone > Blocked Contacts.
4. See if Call Forwarding is turned on. Go to Settings > Phone > Call Forwarding and make sure it's off.
5. Check to see if Silence Unknown Callers is turned on. If the setting is on, a caller must be listed in your Contacts or Recents. Or they must have shared their number in Mail or sent you a message using that number in order for their call to go through. Add their number to Contacts to ensure the phone rings. Calls from some third-party apps might not go through.

Update your software (13.7 is current software on my phone)

1. Check for a carrier settings update.
2. Check for an iOS software update. Some updates might require a Wi-Fi connection.

Remove and reinsert your SIM card

If your iPhone has a SIM card, remove the SIM card, then reinsert it.

Contact your carrier

When you contact your carrier, make sure that:

• Your account is set up to use your iPhone.
• There aren't any localized service outages.
• Your account doesn't have a billing-related block.
• Your calls don't have errors on the carrier system.

Check your network settings

1. Reset your network settings. Go to Settings > General > Reset > Reset Network Settings. This will erase all current saved settings, including Wi-Fi passwords, preferred networks, and VPN settings.
2. Try to make or receive calls in another location.
3. Switch to a different network band. Go to Settings > Cellular > Cellular Data Options > Enable LTE and turn off Enable LTE, 4G, or 3G (this option will depend on your carrier and device model).