I was saying that you could try to set a static IP on Archer C6 WAN interface and that's it. That way you can isolate if the DHCP lease time of the ISP modem is causing the issue. I assume your C6 is...

Try to set your C6 router WAN (internet) interface with static IP (for example 192.168.1.2) and see if that helps.

Have you tried to reset the router ? I've seen similar issues with C7 FW upgrade in the community.

Hello, apart from removing the dust with soft cloth , there's nothing else you have to do to maintain the device in a good condition. Resetting the device is final resort when you have a specific...

It makes sense to move to AX capable device since you've already upgraded your bandwidth.

You're right, turning off is just for the testing purposes. You're using more recent FW than the screenshots I sent - hence the difference. A lot of extras are enabled now I can see, I believe...