socket bind() to port 25 for address (any IPv6) failed: Address already in use: waiting 30s before trying again (5 more tries)Type the following to see what is bound to port 25:
netstat -lnp | grep :25The far right value of the output will likely show the name of the process that is bound to port 25, eg:
tcp 0 0 0.0.0.0:25 0.0.0.0:* LISTEN 24736/postfix
tcp 0 0 :::25 :::* LISTEN 24736/postfix
/etc/init.d/postfix stopor if that doesn't work, we can note the PID number, to the left of postfix, eg: 24736/postfix, so to kill it, use
kill -9 24736where you'd replace 24736 with the PID number that shows up in the output.
sockstat -l | grep :25