I am having the same problem. I have tried to stop, disable camera server 2, and power cycled the rb5. when I am trying to run "rb5-streamer -c 2" it is giving me a server error, so I have used the following commands to restart camera 2.
systemctl enable rb5-camera-server@2
systemctl restart rb5-camera-server@2
But still no luck. I am only able to view camera 3.
Any help will be appreciated!