5g hub ZTE mc888 won’t allow WiFi calling

[Rural]

We have recently switched to Three. We switched from the standard broadband to the 5g hub because we are very rural and our highest speed on the line was 5mb. With the hub we are getting the fastest broadband we’ve ever had. But here’s the problem: it won’t allow us to use WiFi calling. We rely on WiFi calling because signal in the house is awful (old house and very thick walls). WiFi calling worked for us before but won’t with this hub. Can anyone help us with this?

[Hagadol]

What networks are your cell phones on ?

[tsvetanpelovski]

1p mobile (EE)

[Hagadol]

I got Three to do a reset.  Then reset the hub my end.  It makes no difference.  Most of the time WiFi Calling does not trigger.  if I am on almost any other Wifi network, if I turn on Airplane Mode, then turn on Wifi, it triggers Wifi Calling within between 5 to 10 seconds.

iPhone 12 Pro Max on O2.