We did setup the proxy server for http connection at BES 4.1.2 for exchange and it works very fine. However, whenever we try to use the https connection it didn't work and return the error 403. With the detail debug at our microsoft isa server, we found that the BES did connect to the isa server but without sending the predefined username and password over, and so the isa reject the connection. For http connection, it works fine with sending username and password over to the proxy. Does anyone has idea? please help, many thanks.

Hi, I have a same problem with this https request to Proxy server.
In our environment, we normally expect authentication pop-up whenever hitting this proxy. Proxy setting and pac file config seem to be correct since we tested same https connection to same URL from my desktop to proxy and there weren't any problem. But when initiating the request from BlackBerry, proxy seems to be rejecting the request because a user account set to be null before poping up authentication request....

Yes, the error message is "Invalid http proxy: null servername:8080". Do you know any solution?