Mailbox switch tasks do not complete. However, the earlier migration for the same mailbox for which the switch had been performed completed successfully. In the On-Demand core 'Tenants' page, we have granted all the Migration consents for the migration account on the Source tenant and the migration account for the Target tenant.
There are no errors/details on what is going wrong in the event log for the Switch task. Just one event--that the task has started. And then the task just hangs.
Ensure that in both dashboard areas (general 'Tenants' page of On Demand tool and the 'Configure Account' page of the On Demand Migration tool) being used for the migration account of the source tenant and the target tenant are consistent with each other. And that both have been granted the consents.