Different active recording frame

I have installed jitsi-meet and jibri different servers and I can record sessions with the issue decribed below. Plus I could not managed to havedropbox integration.

Two screen shots on left side are from my server and two screenshots on right side are from meet.jit.si server.

What is the reason of the black rectangular area at right side for my server. (Red arrow)
Another issue is if screen is casted the active area is getting even smaller… (Green arrow)

In addition could somebody tell how to install dropbox integration tool.

Thanks in advance.