Hi,
checked email settings in site configuration. Testmail sending works, all other components, plugins and modules using PHPMail function also work. Disabled "Email as system email" in plugin configuration. But no effect.
The account is removed (of course also in database, checked it), so the plugin works so far on the side. But the user, who is sending the request will be confused seeing the error message.
So another issue is responsible for the message.
Best regards
G.