Error Code: 502 Proxy Error. The request is not supported. (50)

[Mr Costas]

I’m having a SBS 2003 Premium with ISA 2004. Due to some unknown reason I’m getting several error messages on certain pages and also with the programs who needs internet access. For example, when I try accessing rhapsody.com, it says “Unable to sign in to Rhapsody. Check your Internet connection, then try again.” It just wont allow anyone to login. There is no problem with the internet connection for sure.

The complete error message is as follows:

Technical Information (for support personnel)
Error Code: 502 Proxy Error. The request is not supported. (50)
IP Address: xx.xx.xxx.xx
Date: 5/13/2007 3:34:54 AM
Server: svr.lan.local
Source: proxy

Can anyone please tell me what to do to fix it?

[Scott2580]

As the problem is with Internet connectivity, I will suggest you rerun CEICW again your SBS to recheck if there is nothing wrong with network configuration. I’m sure you know how to do it properly but still you should check the steps of it from this KB http://support.microsoft.com/kb/825763/en-us.

Once done, open ISA 2004 console, locate on "SBS internet access rules", move this rule to the top and click Apply to save all the settings. Now go to ISA2004 Management Console and expand the Configuration->Networks. Here under Networks panel double click on option "Internal". Switch to "Web Proxy" panel, click "Authentication" button and
then uncheck the "Require all users to authenticate" option. Then click the Apply button to save the changes.

See if still you facing the error.

[Mr Costas]

Thank you very much for the help Scott but there seems to be a small problem. While going through the steps I noticed it requires "schedule down time." Am I making some mistake or it is the part of procedure? As my server remains always busy, I’ll do it while people are still online but I’m afraid if it will mess things up.

[supremer]

Hey guys, I have had this problem in past and was able to fix it very easily. What you need to do is just enable the Compression Filter in ISA2004. You can do this by going to Configuration > Add-Ins > tab Wel Filters > properties Compression Filter > select Enable This filer. > Ok > Apply. This is what worked for me, see if t helps you too.