The client e-mail server, mail.eskimo.com, which provides imap, pop3, and smtp for clients and for webmail, stopped talking to the network sometime last night.
It has been rebooted and is now operational again.
I do not know what is causing it to do this but it is an old centos6 machine that I am in the process of configuring a new server based upon ubuntu 17.04 and the latest versions of all the software to replace the centos6 machine.
Centos6 does not get maintained well by RedHat which is why I moved the incoming servers to ubuntu17.04. Configuring this server takes longer because there are more software systems involved but I am getting close.