Hi Kelvin,
Thank you for getting in touch with us through the Microsoft Community. From your description, it appears your issue is related to hybrid environment.
After discussing with my team, I have some specific redirection information for you. Microsoft has a dedicated community channel where our top professionals and community members can provide support and resources.
Please visit the : Microsoft Exchange Hybrid Management - Microsoft Q&A to share your concern.
Our community mainly focuses on Microsoft 365 Business Exchange Online license subscriptions and email flow within the Office 365 admin center. However, by posting your question on the provided link, you will receive relevant information from our community members.
Thank you for your cooperation. If you have any further questions, please feel free to reach out to us in the Microsoft Community, and we will do our best to assist you.
Sincerely,
Albert | Microsoft Community Moderator