I got an error and dont know how to fix it

I just made a game, built it, and uploaded to community. I went to add a new level but now it has an error and I am new to this and am not sure how to fix. Pls help.
here’s error:
Library\PackageCache\com.unity.package-manager-ui@2.0.8\Editor\Sources\UI\PackageDetails.cs(24,42): error CS0308: The non-generic type ‘PackageDetails.UxmlFactory’ cannot be used with type arguments

I had this same problem, I fixed it by going into the package manager. clicking the packages sort in the top left and clicking “In Project” then finding the “Package Manager UI” package and pressing update on the bottom right.

After that the errors instantly went away.

UxmlFactory cannot be used with type arguments, so when you go to PackageDetails.cs line 24, you are using the UxmlFactory method incorrectly. That’s about as much as I can tell you from just the error, I would really need ot see the code.