I had this issue recently - I think I tried about three different ways. From memory I used the code underneath the qr code “chart” then followed instructions . I also changed the name of the new router (2.4 ) to the old router - can’t remember if that worked . I got there in the end trying various routes from Givenergy websites various and other sites. Not very helpful I know but if a numptie like me got there I’m sure you will. Best of luck
You need to change the code of the new router to that of the old one using the admin setting for the router. Had to do this with a new router for the solar inverter to connect. Easier to change the router than change all the other devices that connect to it.
I have just changed my router. On the original router, I saved all the data on the computer then I loaded it onto the new router. Connection to the EV charger and GivEnergy inverter are still working fine.