The system has not been taken off maintenance mode completely.Please contact your system adminstration.

The system has not been taken off maintenance mode completely.Please contact your system adminstration.

Cause: After patch application, Maintenance mode is not disabled.
In my case, I encountered this error while accessing oracle E-business suite, I started the applications before disabling Maintenance mode which is incorrect.


Solution :
1) Login to applmgr user
2) Stop apache
3) Run adadmin
4) use option 5 to disable maintenance mode
AD Administration Main Menu
————————————————–
1.    Generate Applications Files menu
2.    Maintain Applications Files menu
3.    Compile/Reload Applications Database Entities menu
4.    Maintain Applications Database Entities menu
5.    Change Maintenance Mode
6.    Exit AD Administration
Enter your choice [6] : 5
Please select an option:
1.    Enable Maintenance Mode
2.    Disable Maintenance Mode
3.    Return to Main Menu
Enter your choice [3] : 2
sqlplus -s &un_apps/***** @/apps/vision/apps/apps_st/appl/ad/12.0.0/patch/115/sql/adsetmmd.sql DISABLE
Successfully disabled Maintenance Mode.
5) Restart Apache.

We can even  enable or disable maintenance mode without using adadmin, 
ENABLE maintenance mode:
sqlplus -s apps/apps @$AD_TOP/patch/115/sql/adsetmmd.sql ENABLE
DISABLE maintenance mode:
sqlplus -s apps/apps @$AD_TOP/patch/115/sql/adsetmmd.sql DISABLE

 Check the current status of Maintenance Mode:
select fnd_profile.value(‘APPS_MAINTENANCE_MODE’) from dual;
MAINT     =  MAINTENANCE MODE is ENABLED
NORMAL =  MAINTENANCE MODE is DISABLED