Slow and unstable 2.4 Ghz band connection on Archer C20
I use dual band and 5 Ghz works fine. But 2.4 Ghz is very slow and unstable. Sometimes it works fine but often loses connection (about 5 times in 15 minutes). Sometimes i can't even connect to WIFI. This problem occurs on all my devices that connected to 2.4 Ghz.
Archer C20 is EU version. I bought it 15 days ago and this problem showed up after 5 days of using it.
Firmware is the latest as i checked. I tried to change Channel, Channel Width, SSID. Tried to turn off 5 Ghz and did reset. Nothing worked. Please provide me a solution if there's any. Thank you!