When I open the domain files with the vi editor I have seen an "^ M" appear in the code:
<IfModule mod_headers.c>
Header always set X-Content-Type-Options "nosniff"^M
Header always set X-XSS-Protection "1;mode=block"^M
Header always set X-Frame-Options "SAMEORIGIN"^M
Header always set Access-Control-Allow-Origin "*"
Header always set X-Supported-By "Kloxo-MR 7.0"
RequestHeader unset Proxy early
</IfModule>
I mention it in case it is due to an error when converting/saving the text of the Kloxo forms.
Clients — "Username" — Domains — "Userdomain.com" — {Web Features} => General Header (in Apache Format; Blank To Reset)
I have provisionally cleaned the files with a:
perl -p -i -e "s/\r//g" /opt/configs/apache/conf/domains/*