Hi, I've read this and few similar topics and I think this is the closest to my issue. The only difference at me is that the disconnect happens every hour after reboot, and lasts 2 to 45 seconds then WAN connection is restored automatically.

I have

ER605 v1.0
1.3.1 Build 20231207 Rel.61384

OC200 1.0
1.32.6 Build 20241101 Rel.41525

EAP245(EU) v3.0
5.0.6 Build 20220429 Rel. 44315

I.e. if the ER605 was rebooted at 6:12, the restarts happen between minutes 11-13 every hour e.g. 7:12, 8:11, 9:13 etc. WIFI still works, but the connection to WAN is down on LAN too. Sometimes I get notification in the Omada app that the OC200 is offline, but not always probably because the disconnect is often less than 10 seconds.

The log isn't much useful, all it has is:

Network Disconnection - Cloud access is disconnected due to network disconnection.

And sometimes, but not always is followed by:

Cloud Access Success - Successfully access the cloud.

The ER605 is connected to a fibre modem provided by the broadband provider. The provider investigated on their end and couldn't find any issue, and there were no recent changes to the network config either. I'm behind a provider NAT.

The issue started on 14 November and there was no change in my setup around that time.

IPv6 is not enabled, have DHCP on WAN and LAN too. No IP conflicts in log, only the disconnect/connect.

I've already rebooted everything several times both from the admin interface and by unplugging the power for 30+ minutes, all firmware are up to date, but the issue still keeps happening.

Any ideas what could cause this, and how to investigate in more details?

So I swapped out the ER605 with the provider's router, didn't connect anything to it, used only the WIFI and it reproduced the same error. After I provided the screenshots to the provider (I don't have access to the logs on their router) they acknowledged it's an issue on their end. It took 3 days until they solved it, but at least I have a stable connection again. They didn't share what the problem was.

The error I saw on their router was that the IPv4 connection was reset hourly so could have been DHCP related. The IPv6 connection wasn't reset though.

I am very disappointed with them that they didn't find the error when I first reported. I understand they don't support custom hardware, but they could have looked at the logs in more details when I first asked.

Issue solved, thanks for looking.