Delivery Fails From cPanel Server To Office365← Back
I was performing a test migration from Exchange 2010 to Office 365 using a domain I used to host on my cPanel server. The domain had been removed from cPanel but I was receiving a 550-Unroutable Address error when testing email each way.
The NDR looked similar to:
Diagnostic information for administrators: Generating server: bigfish.com firstname.lastname@example.org my.server.com #
550-Unrouteable address 550 Sender verify failed> #SMTP#
In my case, when I removed the domain from cPanel, it was not removed from /etc/localdomains. I manually removed it from that file and then mail was delivered as normal.