PROBLEM:

The application is unable to connect to the database after it was idle for a long time.
Error ORA-02396: exceeded maximum idle time, please connect again was logged in the application log.

SOLUTION:

First, you need to identify, with which user, the application is connecting to the database. Let’s say the user is SIEBEL.

Now find the value of the IDLE_TIME resource limit set in the profile of that user(SIEBEL)

Here the idle_time is set to 12800 minutes. So if the session is idle for this much time, then it will be disconnected with the error,
Error ORA-02396: exceeded maximum idle time, please connect again was logged in the application log.

To fix this, alter the profile with the IDLE_TIME set to a higher value or UNLIMITED.