Do you get the sign in with app disabled error?
What I do then is to allow the API
There is a workaround:
1. Sign in to https://admin.google.com/ with your super administrator.
2. Click Main Menu > Security > Settings > API Permissions > Trusted Apps
3. Add two web applications with the following OAuth Client IDs:
101545705208641292657
76254656058-
After that, you should be able to install our app for the domain and proceed with backups.
After that, you should be able to install our app for the domain and proceed with backups.