I am using Claws Mail behind a firewall and web proxy. The proxy has a rule that only allows know software to request web content based on the user agent string. When Fancy does a request it doesn't always pass the user agent. From the pcap data I have looked at so far, it isn't sending the user agent on https request. Emails from Sears have mostly URLs that are https. If needed I can supply an email after I redact any account information. I can open the emails in Firefox without problem. I have looked at the code, but I find it a little hard to follow and haven't figured anything out.