@ralphonz thanks.
I have updated my php.ini and wp-config.php to 128M (on my VPS).
Wordfense is running longer, but still hangs with the same error.
I have disabled/enabled the Wordfense plugin. Updated to 5.0.4.
php-info() tells me that I have 128M.
I just wonder, where am I wrong in my memory allocation definitions?
Any hint is appreciated.
Thanks