EM12c : Login to GUI with the correct password causes authentication failure

So the other day I was trying to login to my EM12c R4 environment with the SSA_ADMINISTRATOR user, and I got the error :

Authentication failed. If problem persists, contact your system administrator.

I was quite sure that the password that I had was correct, so I tried with the SYSMAN user and had the same error, but still wanted to verify that I had the correct password , so I tried with the SYSMAN user to login to the repository database, and was successful,
so I know something was wrong there.

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So I went to the<gc_inst>/em/EMGC_OMS1/sysman/log/emoms.log and saw the following error

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Which led me to believe that the JOB_QUEUE_PROCESSES was set to 0, but it wasn’t the case, it was set to 50, but it is actually not a correct limit, so I bumped it up to 1000 as per documentation and tried to rerun the EM12c repository DBMS Scheduler jobs as
per the documentation in 1498456.1

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After this I bounced the OMS , but still kept getting the same error, though it fixed the scheduler jobs, I was now seeing the following error in the emoms.log

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So what I did was an update to the SYSMAN.MGMT_AUDIT_MASTER table and run the procedure MGMT_AUDIT_ADMIN.ADD_AUDIT_PARTITION as was stated in document id 1493151.1

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Once I did this, I was able to login with all my EM12c administrators without any issues.

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Conclusion

Even though the JOB_QUEUE_PROCESSES was not set to 0, it was the cause that it was failing as it was a low value for this parameter, so just be careful when setting up this parameter , be sure to follow the latest installation guidelines.