Contact form an internal email not working

[grapico]

I have several contact forms on websites. Was recently alerted to a problem. When this contact form is sent to any email that is hosted on the same server, it doesn't work. If it is sent to gmail however, it works fine.
What could be the problem or setting that needs to change?

all of these sites are on same server...
a.com
b.com
c.com

if a.com contact form goes to [email protected] ... it won't work. If it goes to [email protected] it works.

 

[stdout]

Your trouble report is brief, at best. Have you looked at the exim logs yet?

A quick and easy way to do would be to "grep" (search) for both recipient/sender.

Hypothetically speaking, let's say [email protected] is unable to send to [email protected]
To search the logs, copy/paste:

grep -i [email protected] /var/log/exim_mainlog | grep [email protected] | tail -n 100

Once you get the "feel" of exim_mainlog logs, spotting failures is a singe. Good Luck!

 

[cPanelMichael]

Hello

Is email for this domain name handled locally? If so, check to see if the domain name that is sending the email is listed in the "/etc/localdomains" file on the system. You can modify the email routing settings for a domain name via:

"WHM Home » DNS Functions » Edit DNS Zone"

Thank you.