Cannot use my assets in package manager

Questions & Answers
1

The issue in console when I clicked the my assets via package manager
IsReadOnly is not implemented by this handler UnityEditor.EditorApplication:Internal_CallDelayFunctions ()

None of my online assets can be imported. the issues is
IsReadOnly is not implemented by this handler UnityEditor.EditorApplication:Internal_CallDelayFunctions ()

Others also met the problem https://forum.unity.com/threads/how-can-i-solve-this-error-with-package-manager.1327386/

2

Customize the preference for package manager again. I resolved it.

Solution: clean/redirect/reset the cache folder for package manager