Unable to receive emails from office 365 using TLS 1.2

I have Exchange Server 2013 with CU 21 and added TLS 1.2 registries on my Exchange Servers. Recently ran Exchange HCW, I am unable to receive mails from office 365 mailboxes using TLS 1.2. I have third party certificate while validating out bound connector on office 365 it shows following error " The validation is failed with error "450 4.4.317 Cannot connect to remote server [Message=451 4.4.0 Socket error SocketError]" when i am enabling TLS on connector settings".