Hi Lijo Louis,
This issue only occurred on this users or other users have same issue?
Please check and make sure all required services are running.
- Please run the following command to check whether the account is in the list or group:
Get-ManagementRoleAssignment - Role "ApplicationImpersonation"
If this account in the group, you also could try to remove the account from this group and add it again.
For more information : Get-ManagementRoleAssignment and Impersonation and EWS in Exchange - Please try to removed Exchange Server network Address (exchange.domain.com) entry from Control Panel\User Accounts\Credential Manager.
In addition, you should set the DNS records and Autodiscover point to Exchange 2016 server after migration.