Unable to import builtin packages from editor

When trying to import packages in the project window I am unable to import anything, the ‘Import Package’ dropdown shows but the only thing in it is the ‘Custom Package’ option. I alos get an error when going through the package manager to the Unity Registry:

[Package Manager Window] Error searching for packages. An error occurred, likely on the server. Please try again later.
Unable to perform online search:

Here’s what I get:

The package registers as enabled in the Built-In section of the Package Manager: