Hi Sridhar •,
Welcome to Microsoft Q&A forum.
As I understand, you are doing Azure Database for MySQL Single to Flexible Server migration and not getting region displayed in the dropdown.
This is strange and should not occur, please check below points:
1). Make sure the DMS service is on.
If the user explicitly stops Azure Database Migration Service (DMS) or if the service is inactive for a period of 24 hours, the service will be in a stopped or auto paused state. In each case, the service will be unavailable and in a stopped status. To resume active migrations, restart the service.
2). Check size.
To support migrations of databases that are 1 TB+, raise a support ticket with Azure Database Migration Service to scale-up the migration agent to support your 1 TB+ database migrations.
If above does not help, I would recommend you to please file a support ticket for deeper investigation and in case if you don't have a support plan, do let us know here so that we can check on other options to unblock you.
Thanks