I'm in the same situation. This used to happen often, years ago when they first introduced GAFYD, and I haven't had an issue in a long time. But looks like things are reverting back now.
Couldn't sign up for Youtube TV with my main account. I could sign up for Google Play Music (formerly Google Music, now RIP) but I couldn't sign up for a family account.
Stuff like that. It gets frustrating after a while.