Menu Component/MaterialUI/(VARIOUS COMPONENTS) can't be checked because doesn't exist

[dwilliams427]

I try to run my Unity project for Android (not sure if that matters or not) but I get multiple errors from the same source saying "Menu Component/MaterialUI/Toaster can't be checked because doesn't exist". When I look for these files, they do exist in its proper place and I don't see anything wrong with them.

Can anyone help me figure out why it is saying these files don't exist when they do?

Here is the screenshot of my work environment (https://imgur.com/ZW5BUTQ)

There is a similar question posted but there is still no solution.