Your account may be suddenly logged out for several reasons. Check this article to see if any of these scenarios apply to you.
Account owner clicked “Log out of all devices”
Account owners have the ability to log out all active sessions. When an account owner does this, you’ll be immediately logged out, and will need to log back in to resume playback.
Authorization token expired
In rare instances, your account may be logged out because our servers can no longer validate your session. Try logging back in to resolve this issue.
Existing sessions are invalidated when a user changes their password. Log back in with the updated password to resume playback.
Time has passed
If you haven’t logged in to your account for an exceedingly long time (i.e. months or years), you may be logged out for security reasons. Log back in to resolve this.
Search the Help Center to find answers or, if you're still having trouble, email email@example.com.