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Failed to send mail: end of file reached for office365

Userlevel 1

Last tested: Jan 31, 2020

If you're following these steps, and running into a "Failed to send mail: end of file reached" error, you are probably using as your Mail Server rather than your specific MX server.

To find the MX server for your domain: type nslookup, then set type=mx, then enter your domain name. For example, if your domain name is

$ nslookup

> set type=mx




Non-authoritative answer: mail exchanger = 0


Authoritative answers can be found from:

> exit


From this example the MX server is "".

You can then enter this as the Mail Server, and the error should resolve.


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