Sometimes CloudManager can lose Data access to G Suite, this is caused by CloudManagers authorisation to use the G Suite tenant expires.
This can affect certain aspects of CloudManager, such as Signature Management, SSO and Synchronization between CloudManager to G Suite.
1.) Go to admin.google.com
2.) Select "Apps"
3.) Marketplace Apps
4.) Ensure that CloudManager is "On for Everyone"
5.) Select CloudManager, and ensure that Data Access has Approval granted.
6.) Grant Data Access.