The Concurrent requests are in Pending status / No Concurrent Manager defined to execute the request

After an Oracle Cloning Procedure from PROD to TEST (that it's not necessary shutdown PROD), without reason, concurrent managers were down, so it's produces these Symtomps: 
 - All service request were in PENDING status. Never ending.
 - All workflows whom launched service requests didn't work.
-..

You can see details below:

Solution: Restarts concurrent Manager in OAS(Oracle Application System)  through OS terminal using script
adcmctl.sh located in ..../admin/scripts//... folder.

1. Stop Concurrent manager.
#adcmctl.sh stop apps/apps

2. Start Concurrent manager.
#adcmctl.sh start apps/apps

3.Check Concurrent Manager status:

#adcmctl.sh status apps/apps

You are running adcmctl.sh version 115.31

Internal Concurrent Manager is Active.

adcmctl.sh: exiting with status 0

4.Check whether Concurret Manager Processes are working.

#ps -ef | grep FNDLIBR

After to apply this solution all service requests have to finish appropiately.

I found solution in this link: https://anandoracle.wordpress.com/2012/07/11/the-concurrent-requests-are-in-pending-status-appears-no-concurrent-manager-defined-to-execute-the-request/

Change date preferences from System Profile function directly

Although the best way for changing date preferences for an especific user is using the Preference link at logging page, see below:

but sometimes user has defined default quick load to form directly  so he cannot access to the preferences page. In this case, your Administrator can change from:
Responsability: System Administrator
Function:System | Profile.
Filter: User (user desired), Profile: ICX: Date Format Mask , keep Enable Profiles with no values

Important: Change System Profile Value is a very powerful tool, however an incorrect use can cause side effects.