We're using an ACM certificate to afford custom CNAMEs in a CloudFront Distribution and an API Gateway API. This was working correctly until we recently moved the creation and assignment of this certificate away from a manual process, into an automated one through CI/CD (serverless + CloudFront). The automated process still performs DNS verification via CloudFront's automated Route 53 verification.
Now when accessing either of these resource (ie. the website, as well as the API that the website uses), you get a net::ERR_CERT_AUTHORITY_INVALID.
Note that when I check the certificate from ACM console, it appears everything is correct (says 'Issued' and 'Success'). Also when I inspect the certificate from the browser, it shows Amazon as the correct root authority.
Am I missing something w.r.t. how Root/Subordinate certificates verify the End-entity certificate?
I've been staring at this for like 3 hours and am completely stumped as to what might be going on...