DKIM signature invalid?

Hey there, I had this same issue and had a customer receiving mail from SES claiming that the DKIM signature was invalid.

What I found is that those tools give incorrect results and that the signature is, in fact, valid.

If you look at the DKIM signatures attached by SES there is the one you have setup along with a second one that AWS attaches automatically. I think that this second signature is causing the "invalid" response, but that is incorrect as the RFC for DKIM specifically says that multiple signatures are allowed.