Email sever not working once CDN active

Dear Expart,

One I added Cloudflare CDN account into my site, and also nameserver added as advise, site was working with CDN except email sever is not working. I can’t send or receive mail by outlook client. So i de-activate Cloudflare CDN and emails are working fine again.
Please let me know how can I fix that problem thus i can re-activate.

Kind regards

Dear Mark Meyer,

Goo morning.

I I enable CDN services, them immediately after email client(ms outlook) stop communicating.

Till now this problem exist note there is error message comes when some email not delivered. I have attached DNS for your review and please advise what to resolve.

Reporting-MTA: dns;

550 5.7.1 Service unavailable; client [] blocked

Please advise thus I can activate cdn and take full service from Cloudflare.

Kind regards,


Where or how did you ‘activate’ Cloudflare? Your nameservers still point to Ipage. I am asking because i don’t know if Ipage is a partner or not.

Dear Mark,

It was activated and I paused once mail was not routing. I added and activated again. Mails are stop working after 2-6 hours later once activated.

Kind regards,


Dear Mark,

After 3-6 hours this below message shows in Microsoft outlook.

Task ‘[email protected] Receiving’ reported error (0x50040900): ‘The server name you entered cannot be found on the network (it might be down temporarily). Verify that you are online and that server name is correct.’

Kind regards,


This is because you cannot put Cloudflare in front of a mail host (it only proxies web traffic and drops everything else) and is explained more fully in the first reply.

However, by way of expanding on that info the best approach for you to take would be:

  1. Delete the CNAME and replace with an A record pointing to This is functionally identical but facilitates subsequent changes.

  2. Change MX record from pointing to destination to pointing to Again, at this point this is functionally identical to current setup.

  3. In your Outlook config change any references to the server to Again, you will continue to access the current server with this setup as both hostnames point to same IP. Should you have any other devices connecting to you mail server, make the same change on them.

  4. Finally, when enabling the CDN do not enable proxying of host This ensures access to the mail host does transit through the Cloudflare network (it can’t) and means traffic such as SMTP etc will continue to work.

Dear Saul,

I have edited a you advise. Please check as attached both.

Please note when Cloudflare activated after 4-8 hours, outlook mails stops working. Would you please check and advice with marking how to resolve?

Kind regards,


Not correct.

You have not done this :point_up: step.


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