Hue administrators can restrict the number of concurrent sessions per user. The default value is 0 to represent no restrictions. In that case, a user can have as many simultaneous Hue sessions, i.e. logins, as he wishes. For security purposes, this can be restricted. When it is, normally the concurrent_user_session_limit is set to 1.
[desktop] [[session]] concurrent_user_session_limit=1
When concurrent_user_session_limit is set to 1 any session, i.e. on a different machine or browser, in excess of 1 is removed by eldest. If a user gets logged out automatically, then he or she can assume somebody else is logging in as his/her credential on a different machine.