Hi @Shuvajit Roy
Based on your architecture, are you adding your domain controllers to an availability group? Depending on the requirements of the availability group, availability groups are not supported on domain controllers.
You can review this document for prerequisites, limitations, and recommendations for AlwaysOn Availability Groups: https://learn.microsoft.com/en-us/sql/database-engine/availability-groups/windows/prereqs-restrictions-recommendations-always-on-availability?view=sql-server-ver15.
If this is not the issue, please provide more detailed information.
Best regards,
Aniya