Cannot defer Auto-Migration of MySQL from Single to FLexible

Hi NeilC,

Welcome to Microsoft Q&A forum.

As I understand, you are trying to Migrate Azure Database for MySQL Singke Sever to Flexible and facing error.

If you own a Single Server workload with data storage used <= 100 GiB and no complex features (CMK, Microsoft Entra ID, Read Replica, Virtual Network, Double Infra encryption, Service endpoint/VNet Rules) enabled, you can now nominate yourself (if not already scheduled by the service) for automigration by submitting your server details through this form.

You can review the migration schedule by navigating to the Migration blade of your Single Server instance. If you wish to defer the migration, you can defer by a month at the most by navigating to the Migration blade of your single server instance on the Azure portal and rescheduling the migration by selecting another migration window within a month. The migration details will be locked seven days prior to the scheduled migration window after which you're unable to reschedule. This in-place migration can be deferred monthly until 16 September 2024.

Did you defer before as well or this is the first time?

If you had deferred before then for the second time it will not be allowed.

And if this is the first time and you are facing this error, then I will suggest you to raise support case for deeper investigation.

Hope this helps. Thanks.