@BerlinOmada 

Did you check the router log? Is there any hint which may related to this issue? How did you make the internet work again?

I think this is mostly caused by ISP side. To locate the issue, you'd better test the internet from your modem when it interrupts.

It is not a "event problem", it is a "hard coded" problem by TP-Link, that every 24h the wan-connection ist broken.

this ist the alert-message:

[WAN/LAN1] of ER605-Router is down.

[WAN] of ER605-Router is down.

...

For example:

If I take on sunday at 11:00am some changes on WAN or WAN1 or WAN2 or other network configuration this procedure is ok for me.

But on monday and now every day at 11:00am (24h later) this interface goes down and up without any change. The one reason for this ist "TP-Links hard coded intervall".

the big question:

Where is the parameter for Omada-Router, that the router do this between 3...4a.m., if exist no reason from the user/admin?

In this case:

SUN 11:00am admin activities

MON 3am reconnect WANx (automaticly)

MON 11:00am no interrupts, because the last event was on 3am

unfortunately I have to repeat myself:
ISP have not time schedule / "Forced PPPoE-(V)DSL separation"

I understand it's not nice to read, but unfortunately it's a bug from the router.

Of course, I can manually renew the connection at night, but that's not a solution, it's just a workaround.

The modem log shows no interruption - nothing!
I also tested two different devices for VDSL2 35b G.Vector (ITU G.993.5). Always the interval from the router side.

TP-LInk must be able to test the connection type PPPoE itself or know the stored cron jobs. It is sad that one does not want the advice to be true.

Firmware for Router ER605v1 is from 08/2021:
https://www.tp-link.com/de/support/download/er605/v1/#Firmware

The problem exists every day.
Anyone who uses PPPoE must know it.