If Sendmail takes several minutes to start, and your PHP scripts hangs when attempting to send emails via sendmail (eg: using the mail() function), ensure that your hosts file has its host name as an alias to localhost.
For instance, your hosts file should look something like this:
[leo@crow ~]$ cat /etc/hosts 127.0.0.1 localhost.localdomain localhost 220.127.116.11 crow
You would want to add your host name to 127.0.0.1:
[leo@crow ~]$ cat /etc/hosts 127.0.0.1 localhost.localdomain localhost crow 18.104.22.168 crow
Once that’s done, Sendmail should start and work normally.