Improvement suggestion for PPPoE connection error message

I'd like to suggest a improvement on a error message for PPPoE connection.

A few weeks ago I subscribed on a new ISP which uses GPON as link (ONU on bridge mode) and PPPoE to identify users, they even have a different username for each customer. At first I wasn't able to make PPPoE connection and on LuCI I was getting message Unknown error (USER_REQUEST) on the IPv4 PPPoE interface. IPv4 shows only Alias Interface (DHCPv6 client) which is correct.

After a few hours trying, after another router reboot, it finally connected.

Yesterday I lost connection and again the same msg was used. Only today I could get in contact with their support and was informed that somewhere on their infrastructure they lost electricity and that was the cause, and when it was solved I got connection back without needing any action on ONU or my router.

I just made a test and turned the ONU off, and got again the same Unknown error (USER_REQUEST) msg.

IDK how the software works for making PPPoE connection and how it identifies and handles error. By the msg it looks like the software is unable to identify the cause or even what the error is.

It'd help a lot if at least it could identify and provide meaningful information on if PPPoE connection is being established and failing to connect, or if the PPPoE link isn't even reaching the router, which would mean the issue is external and not on the router itself.

ATM I can assure that ONU is turned off, therefore there's no Ethernet or PPPoE connection reaching the RJ45 port. I guess that, when their infrastructure was powered down, router RJ45 was receiving Ethernet link from ONU, but no PPPoE.

We might have a msg for when PPPoE connection is being received but something on it is failing and it's not even reaching the login stage. And then when login is attempted and PPPoE server refuses connection, which would mean the username doesn't exist or password is wrong.