Okay, i had to do a write up on this because i spent hours looking through tutorials and even Microsoft’s site lead me astray.. here is a tested working way to get DKIM working through Office 365.
Step 1. Login to the admin center ( you should know how to do this! )
Step 2. Click ‘exchange in the lower right hand menu, after clicking the option to display all items:
Step 3. Click ‘dkim’ in the ‘protection’ area.
Step 4. You will see a list of domains. Click the domain you’re looking to enable DKIM for, and hit ‘enable’.
A message like this will pop up, giving you the DKIM settings to put in the DNS settings of your domain host. The fun part here is that after you select the text, the yellow area showing your CNAME records disappears, so you have to hit ctrl-c to copy it while holding the mouse button down. Thanks Microsoft, lol!
Okay, so what Microsoft doesn’t tell you is the ‘host’ setting for the CNAME records. This is the fun part that you’re probably missing.
The hostname/value combination for this record:
Wait an hour ( or however long it is your nameserver tends to propagate records – this can be between 5 minutes to 2 days! ), go back to the Microsoft Office Admin site, and hit ‘enable’ on DKIM for that domain. If you don’t get a yellow error message, you are all set up with DKIM: