Development System & Network

DKIM validating, but mxtoolbox reports as “DKIM-Signature Not Verified”?

I’m trying to figure out why a lot of emails from one of my sites are not getting through (in particular and

With my server, we have a tool that generates the DNS records for us:

RECORD            TTL         TYPE      VALUE
------            ---         ----      -----
_domainkey        3600   IN   TXT      "t=y; o=~;"
mail._domainkey   3600   IN   TXT      "k=rsa; p=xxxx"

(xxx is the full key)

This is what I have in my DNS record TXT records: comes back with this (which all looks good);

…yet mxtoolbox comes back with:

The frustrating part is that if I check the original email on my own account, it comes back as DKIM valid:

What is the DKIM-Signature Not Verified error telling me? I’m at my witts end trying to get deliverability up (I’ve tried testing via GlockApps and it still comes back with lots of rejections for whatever reason). I must be missing something

UPDATE 2: Unfortunately MXToolbox is still ranking this as a problem. Every other tool says its fine though, so I’m wondering if its a false positive. Using GlockApps I can now see its only the Gmail stuff that gets bounced out of their tests:

I’ve read up about it – and it sounds like we may have shot ourselves in the foot when informing people about the crappy GDPR stuff that came out a while back. We emailed everyone (before it came in), to make them aware we would not be able to contact them if they don’t give us permission. Maybe gmails filters picked that up as spam (as quite a lot of our users are on gmail), and punished us for it. Oh the irony! So now it sounds like the only way around it, is to ask people to check their SPAM box (and mark as “not spam”)

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