You will need to increase the number of allowed connections to use the montage view with more than a small number of cameras. Certain Firefox extensions such as FasterFox may also help to achieve the same result.
To resolve this situation, follow the instructions below:
Enter about:config in the address bar
scroll down to
browser.cache.check_doc_frequency 3
change the 3 to a 1
browser.cache.disk.enable True -> False
network.http.max-connections-per-server -> put a value of 100
network.http.max-persistent-connections-per-proxy -> 100 again
network.http.max-persistent-connections-per-server -> 100 again
If you would like to use Chrome, Internet Explorer, or Microsoft Edge, then you can reduce the number of simultaneous connections by changing your montage view. On the console page, click on the "x monitors" link below the date and time at the upper left of the screen. This will show a popup screen that allows you to select a combination of cameras that will work with those browsers. Click "Select" for the group you wish to see and then click "Apply". Now, when you enter Montage view, only the cameras on the selected group will show.