TypeError: dokuwiki\MailUtils::isValid(): Argument #1 ($email) must be of type string, null given, called in /var/www/001-c3voc.de/wiki/inc/deprecated.php on line 489

An unforeseen error has occured. This is most likely a bug somewhere. It might be a problem in the data plugin.

More info has been written to the DokuWiki error log.