@Gerry-213 Yes, in my case it worked. If TL-WA850RE's DHCP is on Archer VR400's wi-fi was dropping continously.

@terziyski After router hard reset did a hard reset the repeater. Configured TL-WA850RE with wired ethernet cable and now both repeater and router works fine. But I couldn't do advanced configuration...

@terziyski Hi, I've checked all ip's on tp-link Tether app. All wired and wireless connections had correct ips that it should. Called tp-link TR support, hard reset modem with reset button, unplugged...

Hi, tp-link Archer vr400 AC1200 v.3 (Firmware up-to-date) modem has a wireless problem on both 2.4GHz and 5GHz connections. Wi-fi clients cannot establish a continuous and stable internet connection...