It has to use it's own number but will still work with your phone when out of range this way.
It's because you can't have 2 sims with the same number on them.
Do you have wifi calling enabled on your account?
I have WiFi calling enabled on the phone if that makes any difference?
Yes, it's required.
Does it actually work though?
Just noticed there are 2 threads running so a bit confusing, but you need to tick the phone setting to allow calls on other devices but it will only work over 4g when you have wifi and 4g calling enabled and working on your account.
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