Az.Migrate Initialize-AzMigrateReplicationInfrastructure command fails with error: Cannot validate argument on parameter 'ObjectId'

Question

I am trying to run the following command which is part of Az.Migrate package:

Initialize-AzMigrateReplicationInfrastructure -ProjectName MyMigrateProject -ResourceGroupName MyResourceName -Scenario agentlessVMware -TargetRegion "GermanyWestCentral"

And it's failing with this error:
Initialize-AzMigrateReplicationInfrastructure: Cannot validate argument on parameter 'ObjectId'. The argument is null or empty. Provide an argument that is not null or empty, and then try the command again.

The error message is not detailed enough and is not helpful. Why is it failing here.