It's easy to see what the server returns to confirm this is a server problem.

perl -MIO::Socket::INET -e'
   my $s = IO::Socket::INET->new("192.168.0.198:80");
   print $s "GET / HTTP/1.0\r\n";
   print $s "Host: 192.168.0.198\r\n";
   print $s "\r\n";
   print while <$s>;
'
[download]

Note: I omitted Content-Type: application/json from the request since GET requests don't have a body (of any type).