S001 SourceAuthDenied
Google's data import from Exchange Online could not sign in to the Microsoft 365 source, or access was denied.
Why it happens
Google lists S001 SourceAuthDenied (and S002 PermissionNotFound) when sign-in to the Exchange Online source fails or access is denied, for example after the consent or connection was removed.
Where you see it, and what it affects
This code shows in the Google Admin console data import for Exchange Online, at Menu > Data > Data import & export > Data import. Codes are in the user and import reports (see the Error/warning code & description column), which are emailed with the import statistics when an import finishes. In the user summary report, each user shows Running, Failed or Completed. Failed means the import did not complete because of discovery issues, and the import report gives the specific error.
How to fix it
- 1
Step 1
In the Google Admin console migration page, disconnect and reconnect the Exchange Online account.
- 2
Step 2
Run a delta import. Google notes that disconnecting does not affect imports that already completed.
Check that it is fixed
- On the Data import page, click Run delta import (super administrator only) and wait for the completion email.
- In the data import logs, the Emails imported total should match Emails discovered. Gmail can show a lower count because one email with several labels replaces copies in several Exchange folders.
- In the user summary report, the user status should be Completed.
Sources
Full guide: How to migrate from Microsoft 365 to Google Workspace →