please check which version of CCO you are running. All CCO plugins come with a Manifest file in which is configured for which CCO version the plugin should be running. I started this plugin series way back in 2018, so I guess you are running a newer version of CCO as I had in 2018.
So please check the file pom.xml and look for the sap.cco.POSVersions tag in the properties node.
The plugin was once created for 2.0 FP06.
So please adapt this with the version you are running.
And also be aware: I did not test the plugins of my blog series with never versions of CCO. There may be some adaptions needed.