I have a running SQL managed instance that is useable via my on-Prem SQL Studio.
I can create and destroy databases via Portal and on-prem ssms
I made sure ports, 1433, 443, 445, 9354 and 12000 were open.
I can connect via SSMS with my azure AD AND with my Sql login.
I run through the DMS: connect to OnPrem, select a database, continue on to the connect to Target Server
I paste the FQBN of my azure migrated instance name, my sql login and password.
it fails after a couple minutes with Failed to connect, please check error details Error 10060 - SQL Server cannot connect to server.