If you ensured both the subdomain and the domain name were provided when using certbot, then it could be a case where the server is still using a previous cert. I had issues where changing the cert in NameCheap did not immediately take affect. (In the NameCheap CPanel console, cert would be fine, but actually visiting the site would still present the old cert for a while.) There were at least a couple times where it only presented the new cert after I fully removed the old one from Cpanel. Other than that, running out of ideas.
A fundamental flaw in this, is it still involves user data, even if “anonymized”. You can advertise without any user data. We do it all the time. Does a television channel know your gender? Does a radio station know if you bought a car recently? Does the newspaper know your hobbies?