[SOLVED] TFS 2018 - Error during download: System.UriFormatException: Invalid URI: The format of the URI could not be determined

TFS 2018 - Error during download: System.UriFormatException: Invalid URI: The format of the URI could not be determined

I have created a release definition in Team Foundation Server 2018 based on a build definition. When the release is started for the respective build environment I get the following error message:

Error during download: System.UriFormatException: Invalid URI: The format of the URI could not be determined.

This error occurs during the release process "Download artifacts".

Question:

Where can I find this URI in Team Foundation Server 2018 which has an incorrect format?

Solution

I have found the error.

In my build definition predefined variables are used. For example, in this $(BuildTargetPath)\App\YourFavoriteProgram\ specification, $(BuildTargetPath) is a variable defined in the variable group.

However, I had forgotten to include the variable group in the build definition under "Variables" > "Variable Groups".