I have integrated the Dynamics 365 with exchange on premises 2013 and after entering the correct setting I was able to test the connectivity which passes. But when any users try to send emails via dynamics 365 they are getting the error below:
Error : Microsoft.Exchange.WebServices.Data.ServiceRequestException: The request failed. The underlying connection was closed: An unexpected error occurred on a receive. ---> System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a receive. ---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host
- I checked the TLS 1.0, 1.1 and 1.2 is enabled in all the exchange servers.
- Checked the EWS authentication and SSL for all the servers and it looked fine.
- Browsed the EWS URL and able to browse
- Dynamics 365 IP's are also added in firewall allowed list
Found the article below and followed the same which also did not help
Any assistance will be appreciated