HTTP status 401: Unauthorized error

I wrote some callouts that use CRM web service for reading some additional data.

Man I was furious! On the test system it worked, on the production I got the 401 unauthorized error.

I Goggled a bit and then I tried the simplest solution:

• Comment out the code: crmWebService.PreAuthenticate = true;

And it worked!

Guess what? This code was copied from Microsoft CRM 3.0 SDK.