Why cant Office 365 find my CName record for autodiscover?

Question

The DNS is at Cloudflare.

The setup wizard gave me the choice

1) Set up my online services for me. (Recommended)
Next, you'll update your name server DNS records to give Office 365 permission to set up the rest of your online services.
2) I'll manage my own DNS records.
We will provide a list of DNS records that you will need to add for your domain at your DNS hosting provider.

I selected 2 because I am also using mailgun.

I have added 3 DNS records as instructed by advice at portal.office.com The MX and TXT records verify quickly when I add them

However the CName record does not verify

I get the message

Some DNS records are missing. Please make sure you have added them correctly

for host name autodiscover with value autodiscover.outlook.com

The record shows at Cloudflare DNS as

What could be wrong?

The office 365 wizard in the admin ssection will give the detailed info on why it display the error. Please check the detailed log — yagmoth555, Jul 29 '18 at 00:21
@yagmoth555 Can you tell me more on how I can find this log? — Kirsten, Jul 29 '18 at 00:48

score 5 · Accepted Answer · answered Jul 29 '18 at 09:36

I believe the issue here is that you have enabled the Cloudflare CDN services for this record (the orange cloud button on the right in your screenshot).

This causes the address record (A/AAAA) or CNAME record you entered to be used as internal configuration for the Cloudflare CDN (ie, configuration for their HTTP(S) proxies and whatnot), while the records published in DNS are plain address records pointing to the Cloudflare CDN.

This is almost certainly not what you want for Outlook autodiscover services (surely not what you want for that validation to be happy), and simply disabling the CDN services should do the trick (same "cloud button" mentioned earlier toggles CDN services).

Why cant Office 365 find my CName record for autodiscover?

1 Answers1