Now, this might be a problem of one, but for a while I’ve been having sporadic issues with XSplit Broadcaster’s use of my webcam. Sometimes when trying to use my webcam with other, non-XSplit applications, I’d get this:

I understand what is happening here: Xsplit has basically decided that it would be the arbiter of what can and cannot pass from your webcam to the application that’s requesting it. I just don’t know the why. Of course it’s never easy; this interference doesn’t happen all the time to all other apps. Just some of them.
I ran into this last night because after watching BoredGamer’s intro for this Star Citizen video:
I thought, “Hey! Recording an intro using the built-in FOIP (Face Over IP) would be kinda cool. Let’s try that!” So I fired up Star Citizen, went to the COMMS menu under the options, and attempted to calibrate the FOIP.

No dice. This “grey screen of death” was pretty vexing. Searches lead mostly to Reddit and to Star Citizen’s Issue Council (read: bug report) site, and there were few answers. Someone said to use Device Manager and remove all other items under “Imaging Devices” except the webcam (I only had the webcam). Another said issues were solved after their Acer VR headset was physically unplugged (I removed my Samsung Odyseey HMD, but it didn’t help). I shut down GeForce Experience and Windows Game Bar, but the grey window persisted.
Finally, someone said that they looked into the game’s game.log file for answers, so I opened my log file and saw this:

Well! That solved it. The FOIP system didn’t want to use XSplit’s hand-off for it’s source, so it just threw up a grey screen. I promptly uninstalled XSplit and all of it’s supporting files, jumped back into the game options, and was able to bring up the calibration screen without issue.

I’m not entirely sure if there’s a setting inside XSplit which allows me to shut down this guerilla take-over of my webcam that seemed to be in effect even when XSplit wasn’t running. I wouldn’t mind so much from a 10,000 foot perspective if it didn’t play havoc during the times I want the cam to do what the cam is meant to do, but I guess at a lower level having an app — even an app that I authorized and know exists on my system — setting itself up in between my webcam and gawd-knows-what for who-knows-why reasons sounds like a really bad idea.
Hopefully if you found your way here by searching “star citizen foip calibration not working” or something, this info is useful. If nothing else, check your game.log file for more info, but if you have XSplit installed and are having general webcam issues with other apps, this might be the hammer to that particular nail you’re stuck on.