I have it logged on on my phone, tablet and TV.

Sometimes pain in the a** when you switch off your TV and want to continue to watch on your tablet in the bedroom, usually get the "Someone is watching/using the account, please retry" error.
Better if you "properly" exit the app on the TV (instead of just switching the TV off directly) but still got chance to receive that error.

Have to wait a bit before the previous session on the TV is "terminated" and you can start using that account on the tablet.

Yeah, Unifi gave 1 year basic Disney+ subscription free when I signed new contract with Unifi.