pppoE WAN going UP and DOWN in circles

[udippel]

For the rest, a great and perfect installation. But once WAN was activated and configured, it went UP and DOWN in circles. A reboot brought it back to working perfectly okay. Then, after some time, it started again. No chance but to reboot. And when going UP and DOWN, CPU usage went up towards 100 %.

I found an old (2019) post
https://forum.opnsense.org/index.php?topic=13385.msg61575#msg61575
describing something very similar. Alas, there was no answer then.

Just unplugging and replugging an old m0n0wall or a modern pfsense into the same WAN link show nothing of that kind.

Therefore, alas, no chance to use OPNsense for the time being.