When trying to send emails from dynamics 365 it throws the error below:
Error : System.Net.WebException: The request was aborted: Could not create SSL/TLS secure channel.​
at System.Web.Services.Protocols.WebClientAsyncResult.WaitForResponse()​
at System.Web.Services.Protocols.WebClientProtocol.EndSend(IAsyncResult asyncResult, Object& internalAsyncState, Stream& responseStream)​
Exchange 2013 server on premises and the connection has been established with dynamics 365.
There is no issue in setting up the connection and the test also passes but later on when the users are trying to send email from Dynamics 365 it shows above error in dynamics portal
Checked the TLS settings in exchange server
Also checked the Firewall to allow the Dynamics 365 IP addresses . any inputs will be appreciated