iPhone 16 with eSIM. WiFi calling keeps switching off

I have an esim on my iPhone 16 and the WiFi calling keeps switching itself off. If switch it on and the go back later it's off again. We have zero mobile signal at home so it's vital this works. I'll have to switch to another provider if I can’t resolve the issue.

I have exactly the same problem on my iPhone 17pro eSIM. Does anyone have a solution?

Same problem with iPhone 16 pro max, very annoying

Same here on iphone13 mini IOS 26.4 eSIM . Really annoying!! Please can they sort this otherwise we will have to wave goodbye. Contacted support and went through all of the recommended fixes but no joy.