Office 365 to Google Workspace errors and Solutions.

Exchange Impersonation error. Unable to open user mailbox due to impersonation error. Please make sure impersonation is set properly. (11021)

1. Log into to ECP e.g. https://admin.exchange.microsoft.com/#/adminRoles

2. Select the Permissions menu, then Admin Roles

3. Create a new role by clicking on the + sign

4. Give it a name e.g. GSuiteMigration

5. Click on the + under roles and add the ApplicationImpersonation & ViewOnly-Configuration

6. Click the + sign under members and add the admin that requires the impersonation role

7. Save and rerun the migration steps