I thought this would be easier to figure out, but it's been plaguing me for weeks.
"Server Manager cannot connect to xxx. Click Retry to try to connect again"
First, on the server, open a command prompt as Administrator. Run winrm quickconfig and answer "y" when prompted.
Next you need to configure a listener. I did this via Group Policy as instructed here;
Specifically this paragraph pointed me in the right direction;
"Look for the Windows Remote Management and Windows Remote Shell Group Policy Objects (GPO) under Administrative Templates and Windows Components."
Find the WinRM Service settings in Group Policy, under "Windows Remote Management (WinRM)"
Enable "Allow automatic configuration of listeners", then place an asterisk in the IPv4 and IPv6 filter boxes. voila!
run gpupdate /force to speed up the change to the server.
to test this change, from command line type "winrm e winrm/config/listener" and press enter. You should get a "listener" entry back such as this;
Listener [Source="GPO"]
Address = *
Transport = HTTP
Port = 5985
Hostname
Enabled = true
URLPrefix = wsman
CertificateThumbprint
ListeningOn = 127.0.0.1, xxxxxxxxx
If not, go back to troubleshooting.
Dale