If you have changed the /etc/fstab file then change it back as it was before. Since you messed up boot location. That caused for me the booting issue.

If both servers run on the same raspberry you need to enable port forwarding on port 8080 (mjpg-streamer).
After that replace the local address to external address e.g <img src='http://4x.12x.4x.3x:8080/?action=stream' />