@Zuke 

Hi, thanks for posting question here.

When the issue happens, did you fail to acces specific websites always? Or is it random websites?

There are a few different cases related with unstable connection, including WAN connection unstable and wireless client devices unstable.

For WAN connection unstable (Router Internet LED turns red/orange occasionally):

    1) Connect a PC directly into your modem to verify if your ISP Internet is stable.

    2) Make sure the Ethernet cable between your modem and the Router is connected properly, replaced old cables with new ones.

    3) Change the DNS Server of the Router, login the web management interface of the Router, go to Advanced > Network > Internet > Advanced Settings, change the two DNS Servers into 1.1.1.1 and 8.8.8.8.

    4) Go to Advanced > System > Firmware Update to upgrade the firmware of the Router.

For wireless client devices unstable:

    1) Make sure the Router is properly placed, it should be put in open area instead of inside a cabinet or shelf.

    2) Login the web management interface of the Router, go to Advanced > Wireless > Wireless Settings, change the wireless channel into another one.

    3) For 2.4GHz wireless client devices, adjust 2.4GHz channel width into 20MHz, for 5G wireless client devices, adjust 5GHz channel width into 80MHz or 40MHz to avoid interference.

If the issue persists, please contact local support with the result of the above troubleshooting steps.

  @Zuke 

Hi，if your router got public IP address, did you try to change DNS Server as suggested?

You may try to downgrade firmware if the issue happened since firmware update. It is also suggested to contact local support to confirm further if the same issue remains.