Since we have changed
$wgPasswordSender = "Genwiki@genealogy.net"; $wgPasswordSender = "GenWiki Nachrichten KeinEmpfang@genealogy.net";
That's not a valid e-mail address. $wgPasswordSender takes a string that must be a valid e-mail address representing the account to send mail from, not some random string that you'd like to appear in the 'from' field. Hence all attempts to send mail headered as being from that account fail, so you get no messages.
--HM