On the Web Auth profile, we have something called as Session Timeout and Grace period. Client will disconnect and needs to login as per the timer.
Session timeout is how long the client can access the Internet via Hotspot WLAN after login, and cannot be disabled.
When client logins via Hotspot, AP gets the session start time from SCG and counts session expiration time.
AP will disconnect client and client will be required to login again if session timeout period is reached.
For Example: Client logins to Hotspot at 9AM. Session timeout is 1440 minutes (24 hours) by default. They will be disconnected at 9 AM next day. The client needs to login again after it reconnects to AP next day.
Grace Period information: Which is set to 60 minutes by default, If client disconnects from AP at 10:00 AM and reconnects to WLAN after 11:00 AM, then they need to login again. They do not need to login again if they reconnect to AP before 60 minutes Grace Period, or by 10:59 AM.