BRAND_OFFICE_365_SHORT% mailboxes were synchronized at least once after mail began being sent directly to them. To do this, ...

%BRAND_OFFICE_365_SHORT% mailboxes were synchronized at least once after mail began being sent directly to them. To do this, make sure that the value in the Last Synced Time box for the migration batch is more recent than when mail started being routed directly to %BRAND_OFFICE_365_SHORT% mailboxes.