PHP mail not sending to domain
I've configured all my store email (shop email, customer support, webmaster, etc..) to send from 'firstname.lastname@example.org' which is the domain of by store 'storedomain.com'
When 'email@example.com' is the "from" email address, PHP mail reaches every email address we have tested (gmail, yahoo, other domains, etc.) but it DOES NOT reach and email address with "@storedomain.com"
When we change the "from" email address to any other not "@storedomain.com" email address, then the PHP mail reaches every email address including the email address with "@storedomain.com"
We have spent hours with Microsoft Exchange and decided it is not an exchange issue.
We cloned the store onto a local server and the email function works fine in both situations.
We believe it is a hosting server related issue. Any ideas on how to fix this issue?