Hi All, I have been working on this problem for a few days now and still have no answers. I did manage to contact the developer and this is what they are saying;
"Puffin Academy uses TLS to secure connection between Puffin and our data center. In this case, it needs to connect to your HTTPS proxy server first in order to connect our data center. For uncertain reasons, our protocol layer can not work with that proxy server. It reported the SSL handshake via your proxy server is failed (bad certificate). One possible reason is your filtering system (Smoothwall) actually replaced the certificate and become a man-in-middle to filter content in a secure connection. And that cause Puffin failed to connect our servers.
It's definitely a bug that our network diagnostics process didn't find out this issue. But I'm afraid that this issue can't be fixed soon (or can't be fixed anyway?) I would like to thank you again for providing us these information. I will update you if we find a way to work with Smoothwall filtering system."