Sudden reduction in mouse sensitivity when playing Fortnite. What can I do?

When I played Fortnite, the mouse sensitivity suddenly changed. The sensitivity has decreased. This has affected not only Fortnite, but all other applications. I have already uninstalled the mouse and reinstalled it. Nothing changed. There's also nothing visible in front of the mouse sensor. Even with the Windows mouse settings, everything is unchanged. Does anyone have any ideas on what else I can do?

Have the same problem with Overwatch. Suddenly in the game the mouse lags behind a bit. What mouse do you have?

Rapoo V310 gaming mouse

Put the mouse sensitivity in-game in a bit. That has helped me

There's a silver button underneath your mouse wheel. This is there for the DPI speed. So that means you can press them to make your mouse sensitivity faster. If you press it several times, your sensitivity will slow down again.

I've already tried that, and the second DPI level (out of 4) is slower than before.