Maven and GitHub

 I spent half a day trying to upload my package to GitHub Maven following the guidelines GitHub Maven. As usual, it seemed too good to be true to be successful immediately. Most of the time, I was haunted by a mysterious message which failed mvn deploy command.

RROR] Failed to execute goal org.apache.maven.plugins:maven-deploy-plugin:2.7:deploy (default-deploy) on project RestService: Failed to deploy artifacts: Could not transfer artifact com.restservice:RestService:jar:1.0-20210228.194713-1 from/to github (https://maven.pkg.github.com/stanislawbartkowski/RestService): Failed to transfer file: https://maven.pkg.github.com/stanislawbartkowski/RestService/com/restservice/RestService/1.0-SNAPSHOT/RestService-1.0-20210228.194713-1.jar. Return code is: 422, ReasonPhrase: Unprocessable Entity. -> [Help 1]

After several hours I was at the point of giving up. The salvation came from stackoverflow.

Could you try lower casing your artifact ID

It was the point,  "Return code is: 422, ReasonPhrase: Unprocessable Entity" translates as "use lower case".

Wrong:

<artifactId>RestService</artifactId>

Correct:

 <artifactId>restservice</artifactId>