[Leseratte_10]

Wrong as in "invalid username & password" but it still accepted and saved that? Or wrong as in you want to use a different Adobe account now?
There's no button in the plugin settings to do that (to prevent people from accidentally de-authorizing their account) so you'll have to do that manually.

In the Calibre settings, click on "Miscellaneous" then on "Open calibre configuration folder", then a folder should open. In that folder, open up the "plugins" subfolder, then delete the "deacsm.json" and the "DeACSM" subfolder. Then restart Calibre and open the plugin settings again.

I would recommend making a backup of the current authorization ("Export account activation data" in the plugin settings) before deleting, just in case you do want to switch back to this account in the future without wasting one of the six activations.