Hello Jose Luis Extremeiro Varela,
This might be expected. Please refer to the below,
https://learn.microsoft.com/en-us/unified-secops/mto-requirements#review-the-requirements
Configuring Entra B2B should address your concern here. Refer to: https://learn.microsoft.com/en-us/entra/external-id/what-is-b2b
Hope this helps!
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