Hi @Gauthier BANDEL (Société LCI),
Thank you for posting your question in the Microsoft Q&A forum.
Based on your description, your issue is syncing contacts from CRM to outlook.
If you use Dynamics 365, when you use server-side sync, Dynamics 365 contacts and activities (including emails, appointments, contacts, and tasks) are synchronized to your specified email system (such as Exchange). More information about server synchronization can be found in the documentation: Connect to Exchange Server (on-premises) - Power Platform | Microsoft Learn
In addition, using Microsoft Dynamics CRM for Outlook makes it easier to synchronize CRM information with Outlook mail, Personal Planner and Contacts. For more details, please refer to the link: Microsoft Dynamics CRM For Outlook: Why & How To Get Started
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