Call & text on other devices WiFi only

[Anonymous User]

On call & text on other devices my phone number shows as WiFi only and the option to change it too WiFi and mobile networks is greyed out.

[-Robot-]

I think that's because that's service only runs over WiFi. I am sure I read that somewhere

[Anonymous User]

But with my other SIM it gives me the option to switch it to WiFi and mobile data