I cannot get WiFi calling to work it was fine yesterday. My provider is sky

Here is the Apple post from Dec 12th -

Get help

If you can't turn on or use Wi-Fi Calling, make sure that your carrier offers Wi-Fi Calling and that your devices have the latest software. Then, follow these steps if you can't turn on Wi-Fi Calling or make a Wi-Fi call. Wait two minutes before you go from one step to the next.

1. Go to Settings > Phone > Wi-Fi Calling and make sure that Wi-Fi Calling is on.
2. Restart your iPhone.
3. Connect to a different Wi-Fi network. Not all Wi-Fi networks work with Wi-Fi Calling.
4. Turn Wi-Fi Calling off and then on again.
5. Go to Settings > General > Transfer or Reset iPhone > Reset, and tap Reset Network Settings.

gillfromgloucestershire wrote:

I cannot get WiFi calling to work it was fine yesterday. My provider is sky

Contact sky support, wifi calling is their feature.

I am having the same issue - different carrier - T-Mobile

WiFi calling stopped working immediately after I upgraded to iOS 15.2. This was never an issue with the previous versions and the carrier has not made any changes to their compatibility.