I can't add a CNAME to another domain - why and how can I fix?

My zone name is myapp.com. To add automated email security re spam, SendGrid (provider) wants me to add 3 CNAME records of the format:

 - mail.myapp.com             a123.b456.sendgrid.net
 - s1._domainkey.myapp.com    s1.domainkey.a123.b456.sendgrid.net
 - s2._domainkey.myapp.com    s2.domainkey.a123.b456.sendgrid.net

I can't do this. There is no error, the create button just does not work. I can however create CNAME records to my own domain.

Am I breaking the DNS rules or is this a Google Cloud limitation??

EDIT: Screen shot added.

Redacted parts are all myapp.com except the last two which is the SendGrid code. "Respond" is my subdomain. The existing CNAME is just a test to show I can add CNAMEs.


  • Please add non-obscured screenshots of exactly how you're trying to add the records. – EEAA Jan 9 '17 at 23:59
  • When adding the record, try omitting your domain. For instance, for the mail.myapp.com record, just specify "mail". – EEAA Jan 10 '17 at 0:01
  • @EEAA - screenshot added. Re your second comment, I can't do that as myapp.com is hardcoded into the input field. – Warren Jan 10 '17 at 0:13

Ahh, I see the problem.

MX and CNAME records of the same name cannot exist within the same zone. You'll need to rename one of them.

  • Whaaaaaaat??? In all my reading, that was not mentioned! Simple things, hey? – Warren Jan 10 '17 at 0:19
  • Yep! CNAME records are mutually exclusive with the majority of record types. (RFC 2181) – Andrew B Jan 10 '17 at 1:09
  • @AndrewB For once I beat you to answering a DNS question and wasn't stupidly wrong in my answer. :) – EEAA Jan 10 '17 at 1:11
  • You monster. :( – Andrew B Jan 10 '17 at 1:16

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