Knowledge Base

A note on error 500 Messages

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Error 500.19

When Callisto is installed on a server which also hosts WSUS, there is a bug in the  XPress compression schema module (suscomp.dll) installed with WSUS. The 64bit version of suscomp.dll will try to load into the 32bit Callisto AppPool, which causes the AppPool to crash.

So, if you have WSUS installed on the Callisto server, or you see the following error when you try to browse to the Callisto website:

HTTP Error 500.19 – Internal Server Error
Module StaticCompressionModule or DynamicCompressionModule

In an elevated command line, run the following:

%windir%\system32\inetsrv\appcmd.exe set config -section:system.webServer/httpCompression /-[name=’xpress’]

This should fix the problem and it has no impact on ConfigMgr or WSUS functionality.

It is also possible that 32-bit support is disabled by default for the AppPool, in which case in the Advanced Settings for the Callisto App Pool in IIS Admin, check the following setting:

Error 500.0

We’ve had a few reports of customers with a generic 500.0 error immediately after installing Callisto. The main causes of this are:

DotNet 4.8 is not installed. The solution is to download DotNet 4.8 from here

Another reason for this error we hear is that DotNet 4.8 is pending a reboot. Callisto won’t work until this has been completed.