An error occurred when we added a WCF service reference to the client with the following message:
TCP Error code 10061: Unable to connect due to active rejection of target machine
http://localhost:8732/Design_Time_Addresses/TeacherHelperServic
Unable to connect to remote server due to active rejection of target machine. 127.0.0.1:8732 /

Possible reasons:
1. The corresponding service port is not opened
2. Some TCP listening services are not enabled
3. The Client does not match the Serivce configuration
Solution reference:
 
1. Check firewall Settings. Do you open the service port, such as 8732?If not, add the service port as a secure port.
2. Check whether the service hosting process is started. In this case, the service hosting program is usually run for a custom host to host the service.
3. Perhaps a service such as net.TCP Listener Adapter is not started. The Net.TCP Listener Adapter is set to start automatically.