debugging messages being blocked by server

We just got a new web server, and new ColdFusion (v8 to v11) . Working my way through things that worked fine before and don't work now. Trying to figure out if this is a new server/new server settings problem or if this is a new CF version problem. I go into the Admin page and turn on "Robust Debugging", go to the page having the problem and get a message of "Server Error 500 - Internal Server error. There is a problem with the resource you are looking for, and it cannot be displayed." Checked in CF Admin that the connection name is the same as before, and that it works. All OK from there. My network administrator says it's not his problem. ANY SUGGESTIONS?

Thanks,

Kye