Connecting to remote server failed with the following error message: The connection to the specified remote host was refused

Hi. Hope someone can help me.

I had to install a new certificate on our 2013 exchange server.  After having a few issues, I managed to get the certificate working (I needed to run the following command.....

netsh winhttp import proxy ie

However, since then, when I try to run the Exchange Management Shell, I receive the following message....

Connecting to remote server <servername> failed with the following error message : The connection to the specified remote host was refused.  Verify that the WS-Management service is running on the remote host and configured to listen for reauesrs on the correct port and HTTP URL

If I run "winrm enumerate winrm/config/listener" from the command line I get....

Address = *
Transport = HTTP
Port = 5985
Hostname
Enabled = true
URLPrefix = wsman
CertificateThumbprint
ListeningOn = <exchange server IP address>,127.0.0.1,

Any ideas?  I definitely think it's got something to do with this certificate I've just installed.

Thanks in advance.