Here’s my fix which worked well. Just as with the others my Goodwe didn’t want to connect the the router despite good Fibre signal. I then changed tack and using my smart phone as a WiFi Hot spot I used my iPad to log into the Hot Spot standing right next to Goodwe. I connected to Solar-WiFi and logged into the Goodwe Web portal and reset the connections to my iPad Hot Spot, after entering the new setting I restarted the Goodwe wifi (mine doesn’t have the external rest button ; I figured out I could do through the same Goodwe portal after setting up, last menu top left management’). After a day or two I redid the whole procedure changing Goodwe back to log onto my WiFi router which it did instantly and seamlessly. For future issues I shall repeat this successful method. Hope that helps other having similar frustrations