Migrating email to email PRO problem

Hello,
I need to migrate my email to email pro (legacy mx plan : https://docs.ovh.com/ie/en/microsoft-collaborative-solutions/migration-email-address-to-exchange/#LegacyMxplan)
I already bought the new email account, but when I try to migrate it, the new account does not appear in the "destination email".

Can you please help me ?

have you managed to do it? they won't help