How to debug QGIS Server WMS “Download of capabilities failed”?

Question

Currently I am using a QGIS server with a Linux CentOS system. I am attempting the create a WMS in QGIS and upload it to my website. I have followed the instructions in the "Quantum GIS User Guide: version 1.7.0 Wroclaw". I am trying to call the newly created WMS in QGIS by "Add Layer(s) from a server" button. I am very certain I am entering the correct address but I always get this error below

Could not understand the response. The wms provider said:
Download of capabilities failed: Error downloading

http://***************/cgi-bin/projects/qgismapserv.fcgi?SERVICE=WMS&REQUEST=GetCapabilities
Server replied Internal Server Error

Answer 1

You can test whether the WMS service is configured correctly by making the GetCapabilities request directly in a browser

http://***************/cgi-bin/projects/qgismapserv.fcgi?SERVICE=WMS&REQUEST=GetCapabilities

The format of the request in your question is correct, so if you get an error the server is not correctly configured.

You will need to look at the server logs to help you debug your issue(s)