@Nithyanandham singaravadivelu
Configuring hybrid connectivity is a required step to migrate users from on-premises to the cloud and to ensure full Teams functionality. So before retiring the Lync server on-premise, please make sure you have completed the following steps:
Step1:Move all required users from on-premise.
Step2:Disable your hybrid configuration
Step3:Move hybrid application endpoints from on-premise to online.
For more details about it, you can learn it from:
https://learn.microsoft.com/en-us/skypeforbusiness/hybrid/decommission-remove-on-prem
If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.