To configure G Suite as the authentication server,
Log in to console.developers.google.com.
In the dashboard, click Create to create a new project.
Enter the Project Name.
Under Location, click Browse and select the parent organization.
In the left panel of the displayed project details page, click APIs & Services >> Library.
From the available list of APIs, select Gmail API and click Enable. You can use the search option for quicker results.
In the left panel, click OAuth consent screen and choose the User Type.
In the displayed page, provide the Application Name, Application Logo, and Support email of your help desk.
Click Add Scope and choose Gmail API.
The scope will be displayed as shown in the below screenshot. Copy the scope to SupportCenter Plus.
In the left panel, click Credentials >> Create Credentials >> OAuth Client ID.
Click DOWNLOAD JSON to download the file containing the authorization server details. Copy these details to Client Details in SupportCenter Plus.
Provide a Name of your choice.
In Authorized Redirect URIs, copy-paste the Redirect URL of SupportCenter plus.
You have now configured GSuite as the authorization server for your organization using Gmail as the mail server.