1.Run the script for any concurrent request which is going into
pending/running status and upload the output to SR.
2. Verify the incompatibilities from the concurrent program definition
Sysadmin -> Concurrent -> Program -> Define ->
Query on the Program name
How To Troubleshoot Only One Concurrent Job Running at a Time Note 1504743.1
a. Check the value for the following profile options:
1. ‘Concurrent:Active Request Limit’
2. ‘Concurrent:Sequential Requests’
3. ‘Concurrent:Hold Requests’
They can affect the value of pending requests.
b. Make sure no programs marked as run alone.
Reference From Oracle SR