R12 Concurrent Manager not came up

To solve this problem, need to perform the below steps

1.  Stop all middle tier services including the concurrent managers.
2.  Stop the database.
3.  Start the database.
4.  Connect SQLPLUS as APPS user and run the following :

EXEC FND_CONC_CLONE.SETUP_CLEAN;
COMMIT;
EXIT;

5.  Run AutoConfig on all tiers, firstly on the DB tier and then the APPS tiers and webtiers to repopulate the required system tables.
6.  Connect to SQLPLUS as APPS user and run the following statement :

select CONCURRENT_QUEUE_NAME from FND_CONCURRENT_QUEUES where CONCURRENT_QUEUE_NAME like 'FNDSM%';

If the above SQL does not returning any value then please do the following:

Go to $FND_TOP/patch/115/sql

Connect SQLPLUS as APPS user and run the following script :

SQL> @afdcm037.sql;

This script will create libraries for FNDSM and create managers for preexisting nodes.

Check again that FNDSM entries now exist:

select CONCURRENT_QUEUE_NAME from FND_CONCURRENT_QUEUES where CONCURRENT_QUEUE_NAME like 'FNDSM%';