I got a centos machine that I am configuring send mail for. It has been working for the past couple of weeks. But around last week suddenly the sendmail stopped sending emails. var/log/maillog doesn't show any obvious errors. I tried the suggestions in the following post about changing the daemon option to not include the localhost as per post here:
but here is the thing: I got another identical server with the localhost included in the daemon option and that one is working fine.
I found that if I reboot the sendmail service it can start the queued mail messages.
Has anyone seen this before?