OTRS ISSUE - Mails are not getting displayed in OTRS

Problem Statement

Mails of Tetra's OTRS System was not getting displayed for long hours as the mails was not getting downloaded .

Technical Issue

The mails of OTRS are down loaded by a cron defined in otrs user ( system user ) . when tried running it manually it gave error as shown below

su - otrs 
bin/PostMasterMailbox.pl

The out put was

NOTICE: PostMasterMailbox.pl is already running (use '-f 1' if you want to start it forced)!

Resolution

We have removed the process id of "PostMasterMailbox" as shown below and did run the "bin/PostMasterMailbox.pl"

mysql -u otrs -p otrs
delete from process_id where process_name = 'PostMasterMailbox';

Then the mails started downloaded .