I have never seen such a message. It would be helpful to compare what has been written in the update and coordinator logs when this error is logged in the dashboard. The message itself is not very helpful, unfortunately.
MWG-client : POST /Konfigurator/REST/login HTTP/1.1
MWG-client : 0 unknown
MWG-client : ERROR failed to send request / failed to read response
You could check if port 4710 is listening on your MWG installation. It seems that something prevents the update to happen successfully. I think it might be helpful to file an SR with support and send them a feedback so that they can check all the settings and find out whats going wrong here.