Family sharing impossible to set up

I am not able to join family sharing or set one up that works. When my partner sets one up and invites me I get the error “cannot complete this action - this action cannot be completed at this time”. I have restarted my phone, tried on another Apple device, made sure all updates are complete, signed out and back into appleID. Nothing works. I’ve also tried setting up family sharing myself and inviting my partner instead to that one - I still get the same error.