How to configure Exchange Server 2019 for hybrid deployment with Office 365?

Hi @GHAZANFAR NAQUI 
Thank you for reaching out to Microsoft Learn Q&A! 
Based on your inquiry, I understand you're looking for support with setting up a hybrid Exchange Server environment 

Depending on the specific requirements and goals of your hybrid deployment, the configuration steps may vary in detail. As a forum moderator, I do not have access to a dedicated testing environment to replicate user-specific configurations. However, I’m happy to guide you to official Microsoft documentation that provides reliable and comprehensive insights 

Setting up the Hybrid Configuration Wizard 
You can refer to this article for a step-by-step guide: Create a hybrid deployment with the Hybrid Configuration wizard | Microsoft Learn 

Configuring Mail Flow Between On-Premises and Exchange Online 
For a deeper understanding of how email routing works in a hybrid Exchange setup, this article offers helpful context: Email routing in Exchange hybrid deployments | Microsoft Learn 

Hybrid Modern Authentication Setup 
If your mailboxes are hosted on-premises, this guide helps ensure secure authentication: Configure Exchange Server to use Hybrid Modern Auth - Microsoft 365 Enterprise | Microsoft Learn 

For additional context, you may also find these helpful: 

Exchange Server hybrid deployments | Microsoft Learn 

Exchange Server Security Changes for Hybrid Deployments | Microsoft Community Hub 

I sincerely hope this information partially clarifies your situation. Please do not hesitate to reply if you have any updates. 

Thank you for your understanding. 

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