We have had a Gen COM Proxy ASP environment running successfully under IIS for some time, but now after the Proxy is executed from the ASP page it fails with message "Unable to connect to server".
This problem can potentially occur for any IIS or Gen Proxy version.
The message "Unable to connect to server" does not mean there is a problem connecting to the backend Gen server. Rather it means that the *CM.DLL for the Proxy is failing to load. The user tried to re-register the Proxy files and the *AX.DLL registers successfully bu the *CM.DLL file fails to register with RegSvr32 error message "LoadLibrary("....CM.DLL") failed - The specified module could not be found."
After installing the Microsoft Dependency Walker utility (https://support.microsoft.com/en-us/kb/256872) and running it on the *CM.DLL file the Gen runtime file CPRTxxN.DLL was not found (xx represents the Gen release number e.g. 70, 76, 80, 85). This had been caused by change to the System Environment variable PATH which had lost the Gen runtimes directory. Once that directory was added back to the PATH the problem was resolved.