@myxyuan0617,

First things first, check your firmware version compared to the firmware version listed on the download page for your model. If incompatibilities are discovered, they are usually fixed through firmware updates. As you did not list a hardware or firmware version, I cannot check this for you.

I hate to do it, but I may just end up pointing the finger back at your ISP with this one. A lot of ISPs bill during this period, is there a possibility that they are performing some sort of refresh when your bill is paid?

Otherwise, when the disconnect first occurs, have you been able to see the colors of the lights on both the Archer Router and modem?

The first thing to check is that the Modem is not experiencing a blip in its communication.

If all seems well, you should then proceed to the Router's logs when a disconnect occurs, as this may provide some indication of the cause.

When you first configured your network, did you configure the network using the default setting of Dynamic IP?