Hi stockwell123,
Thanks for posting and welcome to our community 🙂
We have seen some instances where if a customer has already signed into the My Virgin Media app first and then tries to sign into O2 Priority (using their Virgin Media credentials) they see the "Something's gone wrong" error message.
If they sign out of the My Virgin Media app (by clicking on the dropdown by account name) and then log into O2 Priority using your Virgin Media credentials again, it should remedy the issue.
Let me know if this helps.
Alex_Rm