Failed to install readyplayerme into unity , what should I do ?

[Cindylanlan]

1. I use this URL: https://github.com/readyplayerme/rpm-unity-sdk-gltFast.git.
   Then I get the error message:
   [Package Manager Window] Error adding package: https://github.com/readyplayerme/rpm-unity-sdk-gltFast.git.
   UnityEditor.EditorApplication:Internal_CallUpdateFunctions () (at /Users/bokken/build/output/unity/unity/Editor/Mono/EditorApplication.cs:356)
   [Package Manager Window] Cannot perform upm operation: Unable to add package [https://github.com/readyplayerme/rpm-unity-sdk-gltFast.git]:
   Error when executing git command. fatal: could not read Username for 'https://github.com': terminal prompts disabled
   You may need to set up a Git credentials helper
   to access a private repository. [NotFound].
   UnityEditor.EditorApplication:Internal_CallUpdateFunctions () (at /Users/bokken/build/output/unity/unity/Editor/Mono/EditorApplication.cs:356)

2.I tried another URL: https://github.com/readyplayerme/rpm-unity-sdk-core.git
[Package Manager Window] Cannot perform upm operation: Unable to add package [https://github.com/readyplayerme/rpm-unity-sdk-core.git]:
Error when executing git command. fatal: unable to access 'https://github.com/readyplayerme/rpm-unity-sdk-core.git/': Failed to connect to github.com port 443 after 75014 ms: Couldn't connect to server
[NotFound].
UnityEditor.EditorApplication:Internal_CallUpdateFunctions () (at /Users/bokken/build/output/unity/unity/Editor/Mono/EditorApplication.cs:356)
[Package Manager Window] Error adding package: https://github.com/readyplayerme/rpm-unity-sdk-core.git.
UnityEditor.EditorApplication:Internal_CallUpdateFunctions () (at /Users/bokken/build/output/unity/unity/Editor/Mono/EditorApplication.cs:356)

3.My git version is :2.15.0; my unity version is 2021.3.23f1;

Thank you and waiting for anyone to help me!