When trying to access
https://beta.bitcointalk.org/, I get the following error:
beta.bitcointalk.org uses an invalid security certificate.
The certificate is not trusted because the issuer certificate is unknown.
The server might not be sending the appropriate intermediate certificates.
An additional root certificate may need to be imported.
Error code: SEC_ERROR_UNKNOWN_ISSUER
That is with current Tor Browser, and whatever roots it bundles (mostly (?) inherited from Firefox). As observed through multiple different Tor circuits over a period of several hours, the same certificate presents with the following properties. I would guess that its chain is not properly configured on the webserver.
SHA-256 Fingerprint:
B9:C3:72:FE:A8:82:A1:C2:9D:A0:E3:A0:43:16:82:CC:29:2A:4A:EA:C7:9F:35:74:A0:C9:6B:63:F7:B5:3F:AD
Serial: 52:21:72:CD:C8:F4:6E:17:BC:66:A0:17:89:4E:DD:E0
CN: beta.bitcointalk.org
Issuer CN: COMODO RSA Domain Validation Secure Server CA
Issuer O: COMODO CA Limited
Validity Begins: 2017-06-25
Validity Ends: 2018-06-27
N.b. also, epochtalk.org apparently does not have TLS at all.
Failure to connect; port 443 not listening?