Red square in upper left corner/black screen when recording games.

[Goularteba]

When I select to capture games like Valorant or Street Fighter V, the only thing I get is a red square in the upper left corner. When I fit the window to the screen everything stays black. I can only record these games in windowed mode. I've already disabled my firewall to see if this was the problem, but to no avail. What should I do?