I have an Archer C60 (AC1350) v2.0 and yesterday its Wi-fi became too slow at the middel of the day (speedtest from my laptop of abou 0.7 Mbps). I also noticed that, if I connect my laptop to the router using an Ethernet cable, the speed grows to 16 Mbps. This does not happen only to my laptop but to any laptop in this room, and I also tested with the same results whem my laptop was the only one connected (by the end of the day when my colleagues left).

A reboot did not solved the problem.

The log shows no errors or warnings.

I have no QoS, but I have activated the Firewall SPI and the DoS protection. But they were already active before this slow-down.

Looking at the forums, I tried to change the bandwidth (it was automatic and I changed to 40 MHz for 2.4GHz and 80 MHz for 5GHz), and the channel (it was automatic and I changed to 6 on 2.4GHz and 40 on GHz - and I checked before that at this area it does not collide with any other nearby WiFi channels)

What has happened for this slow-down, and can I do to fix it?

Thank you.