Malformed DNS server reply

Hello Community!

I have a mailgun account, which I have setup MX records for in Cloudflare. There are still a few errors when sending out emails, mainly: “Sender address rejected: Malformed DNS server reply”.

I have been working with Mailgun support on this, and they have said the following:

It looks like we’re still showing similar values for your MX records:

dig MX +short

Can you remove the trailing “\03210” from these? Your screenshot doesn’t seem to show them, so you may need to double-check this with Cloudflare.

When I look this up in Cloudflare, it does not show any trailing numbers.

Has anyone come across this issue in the past?


\032” is the DNS way to encode a space. Are you sure the MX records don’t say the server is e.g. “ 10”? It should be server “” and priority “10”.


Thanks mnordhoff - that is super helpful information. I have re-added the mx records making sure to not include any spaces, and I have deleted the old ones. I will wait for DNS propagation, and then reply if it fixed the issue.

Thanks again!

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