It is due to roblox updates when you crash in roblox when injecting sk8r.
This problem is very easy to fix.
Just update sk8r, you can click settings -> download the latest version.
If it still doesn’t work, please restart your computer and update your sk8r again. Or else you can try it again later.
Feel free to join our discord server if you need further help.
Note: You should not always update sk8r often if it already works, it may cause bugs due to Roblox updates being inconsistent.