TikTok's algorithm decides what videos appear in the FYP based on user activity, accounts and hashtags followed, location and language, audio preference, "Not Interested" feedback, and more. This is why the content you see can differ between users even if they follow similar accounts or have similar interests.
First, make sure your internet connection is working fine (restart your home WiFi router and modem, or test on cellular data if on mobile). Next, try clearing your FYP by refreshing multiple times, then restarting the app. This might help to resolve the issue if there's a bug or server problem causing it.