mongodb - Clicking on a link doesn't work but copy-pasting the link into url works

Question

I'm not entirely sure what is going on with this? Is there a place I should start? Is it application level, client level, server level?

Note that no one will be able to help because this server is blocked by a firewall. All the other links work just by clicking, except this one (gives 500 error), but if I copy and paste it exactly into the url address bar then it pumps out exactly what I want.

http://<company-server>/aggregate?
  $project[_id]=0&$project[cmts]=1&
  $group[_id][cmts]=$cmts&$group[count][$sum]=1

I am using MongoDB as the backend and HAML as the frontend.