Zyxel SCR 50AXE Stop Working 2.4Ghz wifi after upgrade to V1.20(ACGN.0)

Lau13

Hi,
I upgraded my Zyxel SCR 50AXE to the latest version (V1.20(ACGN.0)), and after that, my 2.4GHz Wi-Fi network stopped working. Sometimes it appears, sometimes it doesn’t, and when I try to connect, it gives an error. It also shows a Wi-Fi network named “SSID,” but I think that was already there before the upgrade.
Has anyone experienced any bugs with this version?

Thanks in advance.