AWS Certificate Manager failed validation due to a Certificate Authority Authentication error

I feel like I'm taking crazy pills, because I've completed this process before and my configuration seems to match AWS' docs. But, every time I request a new certificate, I get this error message (usually less than a minute after making the request):

The status of this certificate request is "Failed". One or more domain names have failed validation due to a Certificate Authority Authentication (CAA) error. Learn more.

I've requested a public certificate with two domain names: "mydomain.us" and "*.mydomain.us". I chose email validation and did not apply any tags. I copied the CNAME record (_1234567890etc.mydomain.us.) into NameCheap and added a CAA record as well.

CAA Record @ 0 issue "amazon.com" Automatic

NameCheap (domain registrar):

Immediately after request:

After validation fails:

Any idea what I'm doing wrong? Thanks in advance.

Edit: More screenshots