How to solve the Error "sendmail dead but subsys locked" sm-client (pid 28752) is running?

 Error "sendmail dead but subsys locked" sm-client (pid  28752) is running - This is because of 2 MTA (Mail Transfer Agent) were sunning same time. Something is trying to start the postfix service also cause this issue.

[root@testserver ~]# /etc/init.d/sendmail status
sendmail dead but subsys locked
sm-client (pid  28752) is running...
First check postfix is running on the server

[root@testserver ~]# /etc/init.d/postfix status
-b (pid  1765) is running...
[root@testserver ~]#

Try to stop the service if not able to bring down the service & kill the process. Then restart the sendmail service.

[root@testserver ~]# /etc/init.d/postfix stop
Shutting down postfix:                                     [FAILED]
[root@testserver ~]#

[root@testserver ~]# ps -ef | grep -i postfix
root      1765     1  0 Jun09 ?        00:02:06 /usr/libexec/postfix/master
postfix   1772  1765  0 Jun09 ?        00:00:03 qmgr -l -t fifo -u
root     25822 24576  0 16:56 pts/7    00:00:00 grep -i postfix

[root@testserver ]# kill -9 1765
[root@testserver ]#

[root@testserver ]# /etc/init.d/sendmail restart
Shutting down sm-client:                                   [  OK  ]
Shutting down sendmail:                                    [  OK  ]
Starting sendmail:                                         [  OK  ]
Starting sm-client:                                        [  OK  ]
[root@testserver ]#

[root@testserver ]# /etc/init.d/sendmail status
sendmail (pid  28421) is running...
sm-client (pid  28429) is running...

Hope it helps