I have just set up my VR400 router and then set up the RE450 range extender to get a OneMesh network across the building. The previous deadspot now has plenty of bandwidth and the internet speed is now consistent across the house. However rather than having two networks (2.4GHz and 5GHz) it has now created another two networks called XXXX and XXXX_5G with an unchangeable password that does not match the original password of the VR400 router. I saw a similar issue here RE300 password issue - Home Network Community (tp-link.com) but I cannot see that this has been resolved as I am still having the issue.

I have updated the firmware to the most up to date version now and still the same issue (1.0.20 Build 230213 Rel.55420n (6985/8575)).

Thanks