Trying to make phone calls and I get a message saying video calling us currently not available

[Android Central Question]

I try to phone a UK landline, or a mobile, it doesn't matter which I select. It comes up saying "Video calling us currently not available Try calling again later or continue the call as a voice call."

Selecting voice call does nothing. The only way to fix this is to reboot the phone.

I'm on Oneplus 6, no mods apart from Nova Launcher, and I'm on EE.