The remote server returned an error: (501) Not Implemented

Huh??? Not Implemented???

That is the error I have been “trouble shooting” for the past… seems like forever!!!

We have an application that uses the Microsoft AppUpdate Components (Microsoft.Samples.AppUpdater.AppDownloader) to handle the updates of our application.

Here is the story:

This application was connecting to a IIS setup that had not been used before for this application… (Important for the story)

The application would run, connect to IIS, see that updates were available, then hang… minutes later… would get the error message “The remote server returned an error: (501) Not Implemented”

The call to AppUpdater.DownloadUpdate() is where it would hang.

Hum… No code has changed yet… This should work.

I modified the config file for the same application to point to the other server… WORKED!!!

Changed back… NOPE!!!

I looked at IIS Settings, verified XML files, asked co-workers… no luck.

Found the fix here.

Under IIS, expand the Web Service Extensions. There is a WebDAV service extension. What do ya know… It was prohibited.

I allowed it and all works well… You can bet I won’t forget about that in the future.