The structure of the CSV file for mailbox migration to O365 should contain the following columns:
- EmailAddress: This column should contain the email address of the mailbox that you want to migrate.
- TargetDeliveryDomain: This column should contain the domain name of the target O365 tenant.
- CSV Optional Columns: The optional columns that can be included in the CSV file are: BadItemLimit, LargeItemLimit, and AllowIncrementalSyncs.
Here is an example of a CSV file for mailbox migration:
EmailAddress,TargetDeliveryDomain,BadItemLimit,LargeItemLimit,AllowIncrementalSyncs
user1@example.com,contoso.onmicrosoft.com,50,100,TRUE
user2@example.com,contoso.onmicrosoft.com,50,100,TRUE
user3@example.com,contoso.onmicrosoft.com,50,100,TRUE
Make sure that the email addresses in the CSV file are valid and exist in the source email system. Also, double-check the target delivery domain to ensure that it matches the domain name of the target O365 tenant.
If the issue persists, you may need to contact Microsoft support for further assistance.