Can’t Disable WP Mail SMTP

Replies: 1

If i click on “Disable”, this message appears:

TypeError thrown
Argument 1 passed to WR_Email_Handler::configure_phpmailer() must be an instance of PHPMailer, instance of WPMailSMTP\MailCatcherV6 given, called in /srv/www/…/wp-includes/class-wp-hook.php on line 287

Can’t do anything inside wp-admin because of this error.
Hope anyone got some hints for me.

Thanks in advance!
Greetz, COM