Multiplayer server errors

[Deadknighton]

I am trying to enter an online server and i keep getting the same error message. "failed to  join sessions, please try restarting your launcher or game".

I have restarted and reinstalled both of these, it isn't the game as i can go on standard servers without mods. I was wondering if there was a way around this?

[JaariAtmc]

Microsoft enforces the use of microsoft accounts now. Mojang accounts are no longer usable for multiplayer minecraft. Yes, you get the generic invalid session error instead of something more descriptive.