permission denied on publishing a new version of a plugin using Gradle

Hi, I justed wanted to automated the publishing of a new version of my plugin to support 2018.2 using Gradle and got the following error:

>>Task :publishPlugin
>>Failed to upload plugin: You don't have permission to edit this plugin

My build.gradle contains the following publishPlugin configuration:

publishPlugin {
  username intellijPublishUsername
  password intellijPublishPassword
}

The login is succesful, because if I change the password I get the error:

>>Failed to upload plugin: Authentication Failed: Invalid resource owner credentials

What should I do to get the publishPlugin to work?

Cheers,
Mark

PS: sources ->  git@github.com:binxio/cfn-lint-plugin.git