Hello! I have seen many people having this issue.
This was how i fixed it!
1. Click on the Minecraft Tab on the left side of the CurseForge App.
2. Click the 'three dots' button next to the Create Custom Profile option on the top side of the CurseForge App.
3. Click Repair Installation option.
4. Play game.
NOTE: You will not lose any modpacks or worlds!