EmonESP will not connect to emoncms.org

I have and Arduino Uno set up with the code to send the power data to the ESP8266 via serial link. Everything works as it should, MQTT etc. no problem. EXCEPT that I cannot get the ESP to connect to emoncms.org. I have checked my account, set up a new write key and nothing works. For the server I enter emnocms.org, for the node name I have tried various names but settled on os_psu, for the write key I copied and pasted the newly generated read / write key from my account. When I press ‘save’ the Connected ‘No’ flashes quickly and stays on No. I am using Chrome on windows 10. I can see the MQTT messages in MQTT explorer. This is, I hope, the last hurdle as I have spent hours trying to get OEM to work properly. Any help greatly apprreciated. BTW I have searched the net and found various references to this problem but no solution. In desperation I will try on another PC and using MS Edge. Yuk!