Go to, https://console.developers.google.com

Create new project Google Console Project

Select console project, Click library and enable Admin SDK library API access

Create OAuth Client ID

Configure authorized re-direct URI's with format i.e. <BASE_URL>/plugins/googlegroupsync/manage-googlegroupsync.action

E.g. If Jira base URL: http://confluence.ilaesolution.com

Then authorized re-direct URI will be:

http://confluence.ilaesolution.com/plugins/googlegroupsync/manage-googlegroupsync.action

Click on OAuth Consent Settings and authorize your Jira host domain (e.g. confluence.ilaesolution.com )

Copy OAuth Client ID and Client Secret for Google Groups Sync for Jira Plugin