Currently, with MFA enforced admin accounts in the Admin pool, running migrations using Admin account pool is not possible due to the multiple unexpected identical MFA authentication dialogs popup when MNE Migration wizard tries to get the M365 access token to initialize and launch the migration worker threads.
The identical MFA authentication dialogs are from Microsoft 365 when MNE migration wizard initialize the migration worker threads and requires M365 access token for migration. Since MNE Admin Pool manager mitigates M365 throttling by using a different admin account for each migration thread, the request for M365 access token using Admin User name and password will trigger multiple MFA authentication dialog, one for each migration thread during initialization.
To prevent multiple unexpected MFA authentication and mitigate M365 throttling, our recommendation is to create multiple MNE servers, each MNE server configured to use a different Admin account in the Admin account Pool, and unselect the "Use Admin account pool" checkbox on each MNE server.
Please refer to this article regarding MNE 4.17 Admin Account Pool, and MFA
