Why postfix failed to start?

Issue

• Why postfix failed to start?
• Found following messages in system log :

Mar 27 12:34:33 RM_EMG01 setroubleshoot: SELinux is preventing master (postfix_master_t) "read write" to ./master.pid (var_run_t). For complete SELinux mess
ages. run sealert -l 7eb6d11f-7567-45b5-9b76-3193a88afeba

/var/log/audit/audit.log file log:-

type=AVC msg=audit(1332866073.535:6): avc:  denied  { read write } for  pid=3034 comm="master" name="master.pid" dev=dm-0 ino=8421445 scontext=system_u:system_r:postfix_master_t:s0 tcontext=root:object_r:var_run_t:s0 tclass=file
type=SYSCALL msg=audit(1332866073.535:6): arch=40000003 syscall=5 success=no exit=-13 a0=8db0640 a1=2 a2=0 a3=0 items=0 ppid=3033 pid=3034 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="master" exe="/usr/libexec/postfix/master" subj=system_u:system_r:postfix_master_t:s0 key=(null)