I performed a test at http://www.mail-tester.com/ and the score was really bad. Largely due to DKIM signature is not valid. How do I make this valid? I did a search for DKIM in the setup guide and there’s only one instance it’s mentioned at the bottom of the page in the Systems Checks section where if you want to double-check that your system is configured correctly.
The error said:
We were not able to retrieve your public key.
Please ensure that you inserted your DKIM TXT DNS record on your domain ********.com using the selector mail.
If you recently modified your DNS, please be patient and test again your Newsletter in 12 hours, it may take some time for the DNS to be propagated
Yesterday I added this TXT record and I think it corrected this issue:
v=spf1 a mx ip4:173.230.xxx.xxx ~all Default
I ran the mail test again and my scores have improved a lot. It went from 4.9 to 6.9. However, now want to improve the score even more. Here is the latest issue.
You’re using Linode for DNS, not MIAB. To resolve the DKIM issues you’ll need to add the DKIM records listed under System -> External DNS, into the appropriate DNS for the domains you’re trying to send mail for.