They tell you to come back when you’re ready to take the test. This can’t be surprising…

Most institutions use a remote test proctoring service. Before the test begins, the service verify all the requirements are met.

Anything short of all the requirements and they do not administer the test. In the case something is broken, there is usually a window rather than a specific time when you can take the test, so you have an opportunity to resolve it.

If a webcam is required, students are informed about this requirement before enrolling in the institution, and are usually required to purchase hardware capable of doing this as a condition of enrollment.

You get a working web cam. It's a requirement for many remote proctoring services and if you don't have access to one you're screwed.

I get why they use it, without it there's no way to know you're not on your phone or another device cheating since they can only really see what's on the device you've installed the proctor software/rootkit on.

Sadly Linus Tech Tips video of him taking the CompTIA A+ exam has been taken down after threatening letters from CompTIA but they demanded a basically baren room, 360 photos and spotless web cams.

Webcam is broken is now pretty universally interpreted as I don’t want to be on video.