Lately, there has been some major email problems at a couple of major well known reseller hosts that use the Cpanel/WHM with Exim combination. In many cases email have not arrived at users mailboxes. When doing my own tests, most arrived, some got delayed for a couple of hours, and some NEVER arrived. In fact many bounce back with Exim undeliverable messages after 24 hours. Unfortunately there is no pattern and it seems to affect multiple servers so is very difficult to debug according to the hosts. Thse hosts do not know how to solve the problem and are still looking for answers. Unfortunately, some of us resellers simply do not have the time to waste waiting or have any excuses left for our poor customers who don't have a reliable email service anymore. Does anyone have any experience of emails not arriving at the pop accounts with Cpanel/Exim?