Reproduction steps:
1. Authenticate to the registry and create ".upmconfig.toml" file
2. Create a new project
3. Open the Project Settings window and select the Package Manager tab
4. Create New Scoped Registry (see notes)
5. Open the package manager

Expected result: Registry loads with all accessible packages
Actual result: Registry isn't loading any package from the registry and throws errors:

[Package Manager Window] Cannot perform upm operation: Unable to perform online search:
Access to REPOSITORY was denied [Forbidden].
UnityEditor.EditorApplication:Internal_CallUpdateFunctions ()
...
[Package Manager Window] Error searching for packages.
UnityEditor.EditorApplication:Internal_CallUpdateFunctions ()

Reproducible with: 2019.4.33f1, 2020.3.24f1, 2021.2.4f1, 2021.1.0b1

Notes:
- URL should be UNITY_URL
- Scope should be UNITY_SCOPE