Login to Linux Server via SSH.
ssh root@example.com | PASSWORD
* First check the qmail status.
#service qmail status
env: /etc/init.d/qmail: Permission denied
* Check the attribute
# lsattr /etc/init.d/qmail
----ia-------e- /etc/init.d/qmail
* Change the attribute
# chattr -ia /etc/init.d/qmail
-bash: /usr/bin/chattr: Permission denied
* Now Check the permission of /usr/bin/chattr
ll /usr/bin/chattr
---------- 1 root root 10456 Apr 1 06:06 /usr/bin/chattr
* Change the permission to default /usr/bin/chattr
# chmod 755 /usr/bin/chattr
[root@vps-1177201-25132 ~]# ll /usr/bin/chattr
-rwxr-xr-x 1 root root 10456 Apr 1 06:57 /usr/bin/chattr
* Change the attribute of /etc/init.d/qmail
# chattr -ia /etc/init.d/qmail
* Now change the permission of /etc/init.d/qmail
# chmod 755 /etc/init.d/qmail
* Now try to start qmail
[root@vps-1177201-25132 ~]# /etc/init.d/qmail start
Starting qmail: [ OK ]
[root@vps-1177201-25132 ~]# /etc/init.d/qmail status
qmail-send (pid 2477) is running...
Cheers!!