Plugin I created is asking for a license key I created a plugin for a client website and I keep getting license issues popping up in the admin panel for it. Not sure what I am doing wrong here. Obviously I have no intention of putting it into the store, I just want to remove this license key issue.
Craft checks only the handle of your plugin to detect license mismatches. So when your plugin has the handle importer and another plugin in the store has the same handle it will mark it. (since importer is already a plugin in the store it's likely the issue)

The only ways to solve it


change your handle to data-importer or whatever might be unique
make a module out of it
(include CSS to remove the message and ignore it)