FritzBox 7530 with PN Full Fibre - Frequent PPPoE timeouts

For the past couple of months, I have been experiencing frequent PPPoE timeout disconnections on my PlusNet Full Fibre 300 service.. The service is otherwise very good quality with no dropped packets and low latency according to TBB tests.

These happen at fairly random times of day, sometimes two or three in a row within an hour, sometimes just one a week.

I have a 4G USB stick on the FritzBox which kicks in successfully each time, so I don't completely lose internet connection while the FritzBox renegotiates.

I reported the issue to PlusNet last month and they were their usual unhelpful selves, first insisting I use the PlusNet router, then wanting me to factory reset the FritzBox both of which would involve redoing a load of reserved addresses and port forwarding rules which I wasn't prepared to do.

At their request, I did a factory reset on the ONT which seemed to improve matters for about a week then the problem returned.

FritzBox was on version 8.21, since updated to 8.25. The update made no difference.

The Fritz log typically shows: (today's instance)

09.06.26 07:40:23 Failover protection: The primary internet connection is available again.
09.06.26 07:37:44 Could not establish IPv6 internet connection: No response from DHCPv6 server (SOL).
09.06.26 07:37:23 Internet connection established successfully. IP address: 80.189.nnn.nn, DNS server: 212.159.13.49 and 212.159.6.9, gateway: 172.16.14.26, broadband PoP: acc-aln1.tlh
09.06.26 07:37:18 Internet connection established successfully. IP address: 192.168.8.107, DNS server: 192.168.8.1 and 192.168.8.1, gateway: 192.168.8.1
09.06.26 07:37:18 Failover protection: The primary internet connection is currently not available. The backup connection will be enabled.
09.06.26 07:36:48 Timeout during PPP negotiation.
09.06.26 07:36:48 Internet connection cleared.

Sometimes, I get the same PlusNet IP address, sometimes a different one.

The ONT in the living room (front wall of house) is connected to the router via a professionally installed Ethernet Cat 6e wall socket to a patch panel in the loft and back down to a wall socket in the study where the router sits(back of house). Total cable run from ONT to router is about 18 metres.

All patch leads are Cat 6e. I have changed both ONT to wall socket and wall socket to router leads. No difference.

Any suggestions about how to pinpoint the cause of the timeouts and where to go next with PlusNet?

As a starting point can you save your current configuration through the FritzBox interface? This page suggests you can. If so you can save the config, do the factory reset, let Plusnet check things out then reload your config.

PlusNet closed the problem after recommending the factory resets, saying if the problem persisted after resetting I should buy a new router. i.e. a complete denial that it is anything to do with them. So there doesn't seem to be any point in resetting unless there is a clear indication of what is going wrong and why.

What I was after here is some idea of what causes the PPPoE timeout and / or the "Connection Cleared" status that initiates the attempt to reconnect.

Since no-one has leapt in with experience of a similar problem, I'm guessing it isn't a common thing, so I'm on my own.

Oh well...

I've had this a few times on a Zen/Cityfibre connection. Mostly during the night (29 disconnects ) but don't know if it was some sore of maintenance but I did have it during the day once.

I assume you don't have any range extenders like the 3000AX?

Thanks, no, no range extenders as such.

I use hard-wired wireless access points around the house wired back to the router via various switches. Each operates independently of the others. I am pre-mesh. (Mostly pre-WiFi - I can see a cable and know what it does).

For info, I have now bitten the bullet and done a factory reset on the FritzBox. Slightly painful, but now seems to be up and running again. I await the next PPPoE timeout.

Should also have mentioned the FritzBox is also acting as a DECT base for two FritzBox C6s, and using A&A for VOIP, which make it difficult to switch to the PlusNet router for testing..

However, I am thinking of pre-configuring the PlusNet Router with the FritzBox address ranges and port forwarding so I can plug it in as a spare if necessary and switch the VOIP to route to my mobile when the FritzBox isn't available. But that's another story.

If you won't swap in the router Plusnet have provided to use with the service in order to rule out the Fritzbox as the issue then I'm not sure what you're expecting them to do. Maybe Fritzbox can expose a more verbose level of logging that will shed some light on how it thinks it's losing the PPP session.

Edited by jpm (Wed 10-Jun-26 12:35:41)

In reply to a post by Axolotl:

PlusNet closed the problem after recommending the factory resets, saying if the problem persisted after resetting I should buy a new router. i.e. a complete denial that it is anything to do with them.

In a sense they are right. The reason they supply a router is to avoid responsibility for the oddballs like you [and me] who want to use our own routers. For the brief period that I had to use such an ISP, I accepted that if support was required, I would have to use the supplied router, which was a right pain, because I could not even set my own private address range for my own network.

If you are keen to use your own router, then go to an ISP which does not supply a router and pay a little more.

In reply to a post by Axolotl:

For info, I have now bitten the bullet and done a factory reset on the FritzBox. Slightly painful, but now seems to be up and running again. I await the next PPPoE timeout.

do keep us updated on this reset

In reply to a post by Axolotl:

However, I am thinking of pre-configuring the PlusNet Router with the FritzBox address ranges and port forwarding so I can plug it in as a spare if necessary and switch the VOIP to route to my mobile when the FritzBox isn't available. But that's another story.

Again do this and see if the PPPoE disconnect go away. You may need a new router.

also if the fritzbox allows- go back a firmware edition.

There is a hard truth that, sometimes routers get old and can't do the job anymore. There is also a sitation where you just ask too much of it and it will burp and disconnect and reconnect. I had this happen on a low end tp link archer router. Had a new phone with wifi calling and the archer played up and i couldn't keep a connection

When I used to use a fritzbox on my former Plusnet FTTC connection I had a similar problem. I believe I made sure the "permant connection" button was ticked and changed to PPPoA and it seemed to sort it. Dont know if that will help your case though.

After I reset the FritzBox, nothing happened for about a week, then the disconnects started again. This time in the small hours .

Latest at 04.30 ish lasted about six minutes before connection was re-established. That was followed by another brief disconnect at 09.40. In each case, the same PlusNet iP was assigned. That was Yesterday morning. Today, no disconnect so far.

When I have time, I will try the other suggestions that have been made. One at a time, so if any work, it will be obvious what the cause was.

Since it takes up to a week before the problem occurs, there may be a long gap between postings.