Migrating from O365 or other to GSuite you get an impersonation error as follows:
Exchange Impersonation error. Unable to open user mailbox due to impersonation error. Please make sure impersonation is set properly. (11021)https://ssl.gstatic.com/apps/cpanel/resources/img/tooltip.svg
Successfully migrated 0 emails
0 emails failed to be migrated
Impersonation for the mailbox is not allowed.
The administrator account provided does not have the ms-Exch-EPI-May-Impersonate permission on the user or contact that it is trying to impersonate, or on the mailbox database that contains the user mailbox. Correct the impersonation settings and see the EWS environment (Exchange 2007 and later) troubleshooting section for more information.
Log into to ECP e.g. https://outlook.office365.com/ecp
Select the Permissions menu, then Admin Roles
Create a new role by clicking on the + sign
Give it a name e.g. GSuiteMigration
Click on the + under roles and add the following
Click the + sign under members and add the admin that requires the impersonation role
Save and rerun the migration steps