Solved AC86U suddenly no internet connection, even after factory reset

[Inrumpo]

Hi everyone,

I'm currently experiencing a very strange problem and I've run out of options. Now I hope someone around here can help me.

Environment:​

• Asus RT-AC86U
  • Asuswrt-Merlin 386.1_2 (now 386.3_2)
• Samsung 32GB USB stick with:
  • AMTM
  • Skynet 7.2.6

Issue:​

I've ben running the setup mentioned above for months without any issue. Out of nowhere my TV wasn't able to connect to the internet anymore (connection to the router did work).
I then found that all devices not running through a VPN didn't connect to the internet anymore. This behavior reminded me of a VPN kill-switch; the only problem being that I haven't configured such a kill-switch.
I then decided to let things rest over night so see if the issue will disappear as magically as it appeared in the first place – no luck. Things got worse: The next morning not even my VPN connection did work anymore. The result: No internet connection on any device. The router itself seems to be connecting to the internet though:

At first, I was still able to connect to Skynet using PuTTY, then Skynet stopped working as well:

The issue seemed to get worse by the hour. Later I wasn't even able to properly load AMTM anymore.

What didn't help:​

I tried different things to solve the issue. All of the following did not work.

1. Disabling Skynet firewall
2. Rebooting router
3. Updating router firmware from 386.1_2 to Asuswrt-Merlin 386.3_2
4. Factory resetting router
5. Remove USB stick plugged into router

Since not even factory resetting my router did help, I'm puzzled and somewhat out of options. What could I try next? Any log entries I should look out for?

Any help is appreciated. Thank you.

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Solved (for now)​

I had to think outside the box – literally. My ISP's modem was at fault.