Email from a single domain (university) not being received at VPS/Cpanel
I have a problem where all email sent from uaccb.edu (studentmail.uaccb.edu [188.8.131.52]} is not arriving at my VPS. The people sending email from the above domain are not getting any errors, it is not being marked as spam, it is just being blackholed somehow.
I have checked the above IP and domain, and can't find it on any blacklist, and I am using pretty standard cPanel setup on my VPS. I have spam set to be marked and receive a fair amount and have it autorouted to a folder rather than auto-deleted.
From uaccb.edu, the only thing I have access to is Outlook Web Access to send test emails, and they are sent fine with no errors returned. If I send test emails to gmail and other similar email accounts, they go through fine, the only problem is to ANY domain hosted on my VPS. I have even recently transferred all the domains to a second VPS (with the same hosting company) at a different datacenter (for different reason) and the problem persists.
Is there any WHM setting or any ideas on how to troubleshoot this?