Sequoia 15.1 and wifi calling incoming call issue

Now I wonder why I didn't think of that to begin with--great idea!

Actually, I solved the issue. I placed the iPhone and iPad in Airport mode, and turned them off. I shut down both computers. I then turned the iPhone back on and walked through all of the settings for WiFi Calling, including confirming my Emergency Address. This is really pretty simple but it's easy to overlook a step, especially with several devices. The steps are:

1. Go to Settings
2. Select Phone
3. Select Wi-Fi Calling
4. Turn on Add Wi-Fi Calling For Other Devices
5. Go back to the previous screen and select Calls on Other Devices
6. Turn on Allow Calls on Other Devices
7. Turn on each device you want to use with Wi-Fi calling 

Somehow #7, where each of my devices were listed, my MacBook had gotten turned off, and I didn't know that list existed, or rather that you have to go back to the previous screen to find them.

I do not have a VPN, but your suggestion did have me check for network firmware updates, and I discovered that I needed to do that. It did not resolve the issue, but at least I took that variable out of the equation.

I am not sure what your point is, except to say I neglected to mention my mobile cellphone carrier is AT&T. Again, WiFi Calling had been successfully functioning for me on the above devices until a recent update of Sequoia, and is NOW working on all but the 2021 MacBook Pro M1--an update since my original post. It can make calls but not receive them.

Ah, but that's just it--that Function is not working properly on my 2021 MacBook Pro M1 after updating to Sequoia 15.1.1. It had been working previously, and I do not understand why it has ceased. I can relay outgoing phone calls, but I cannot relay incoming calls on only this one device.