Cannot edit IVR - page does not load

I have a working IVR that I am unable to edit because I the page will not load. I have two IVR’s on my FreePBX server. The first is very small with only six options - that page loads just fine. The second IVR is large with about 150 routing options. That page will not load. I can access the IVR menu, but when I select the large IVR the browser returns a “no data received” message with a “reload” & “cancel” option (Chrome browser). I have also tried IE and Firefox - similar results. Has anyone else seen this? Is there a fix?