I've actually run into two sites that I can't access from behind the Astaro, but the webmaster of the first site was kind enough to have instructions on adding a rule to a firewall to access their particular HTTPS site. THIS one, however...
https://www3.sctax.org/DOREPAY
Hangs when you try to access it. The Packet Filter log shows that the HTTPS traffic is going through fine (443), and there don't seem to be any issues in the HTTP content filter logs or anything. I'm guessing that there may be a non-standard port in use, but nothing's raising any flags in the packet filter that I can see.
This thread was automatically locked due to age.