Office 365 no longer receives certain mails

Not applicable

We now run into the problem that certain mails are no longer received. These are sent from on cpanel but never arrive at office 365. We have checked all records of our panel and they are correct. When we send a mail we also receive no error message from office 365. Mailing from office 365 to cpanel succeeds. Oddly enough this worked yesterday, and now it has stopped (without us making any changes)

we have checked the e-mail flow and we can not find the e-mails there. In one way or another, they really do not arrive. We used all kinds of tools to see if the spf records and dkim records were correct and this was correct. It's pretty annoying because the leads come in at office 365 and this does not seem to work. What can we do?

13 Replies

Have you checked with cPanel if the mail ever leave theire service?

Firstly thank you for your reply, but I have sent a copy (c.c) to my Gmail and get it in my mailbox. So I can assume that the mail is sent
I also checked it
The wording here is kinda ambiguous.

Do you have two domains, one with MX records set to Office 365 and one towards the MX of your domain provider?

I could check your DNS if you like. If you don't want your domain in public, feel free to send me a private message and I'll take a look.
Just an update, in case anyone is interested in this case.

We checked and confirmed that the DNS is set up correctly. Daan will check if the problem persists if another domain is trying to send emails to the their tenant and this doesn't work, the next logical thing is to contact Microsoft support.

I have tested sending from one domain to another inside office 365 and that works fine. But when I send using another system than office 365 it won't work (Direct admin / Cpanel)

So O365 to O365 works, but not for example Gmail to O365?

Gmail to O365 yes.
But Cpanel, Direct admin to O365 not it don't even reach the exchange (according to office 365 support)

Sounds like cPanel is set up incorrectly in some way. It's been some years since I've used cPanel but do you have any SMTP-settings you can take a look at there?

I have tested sending an email to another o365 mail and that works fine. To an university that uses office 365


Just got called from Microsoft UK they checked the DNS records (DNS was fine). They are still searching for the problem

Did they find a solution?

I have sent them a YouTube video from our side, that everything works on other office 365 installations (from other organizations). Cpanel also works with gmail. They are still searching for the problem and yes it takes a long time