Hey Ron!

Try disabling Security Defaults for your MS account just until you are finshed with the migration. I had this same issue the other day using BitTitan's MigrationWiz to migrate from a SM account to a MS account.

According to this blog, they have disabled the ability to "enable basic authentication" https://techcommunity.microsoft.com/t5/exchange-team-blog/basic-authentication-deprecation-in-exchange-online-september/ba-p/3609437

And last we checked there is nowhere we can disable security defaults at MS365 to run the migration tool. It appears the migration tool only supports basic authentication. We have tried all 3 Exchange, Outlook.com, and Office 365 options. 

They have disabled basic authentication for:

MAPI

RPC

Offline Address Book (OAB)

Exchange Web Services (EWS)

POP

IMAP

Exchange ActiveSync (EAS)

Remote PowerShell

We need OAuth2 support in the migration tool moving forward. We get quite a bit of people switching to us from Microsoft and are only able to do manual migrations through outlook at this time, which is a pain!

Hi everyone,

Good news to share - this functionality is coming soon! Our upcoming major release of SmarterMail includes Microsoft OAuth2 support for OneDrive connections, mailbox migration and email retrieval. 

Feel free to give it a try now on the BETA build, and let me know your thoughts!