Hi all,
I have a weird issue and maybe someone also encountered this… I searched for similar issues and found some issues resembling this one, but not my exact issue. So here it is in short:
If I connect anything that runs on 100Mbps on the WAN port of my Max BR1 pro 5G (firmware version 8.4.1), my router says “cable not connected” and all lights next to the WAN-port go dark.
It does not matter what I connect to the router. If I manually set the speed to 100Mbps it will always fail. Setting it back to 1Gbps will resolve the issue instantly. So it is very easy to reproduce.
Setting the WAN port on the peplink router to 100Mbps in the GUI does not solve this.
I also had a second Max BR1 pro 5G still running 8.4.0. This one works fine with 100Mbps links. To test if it is related to firmware I upgraded the other router from 8.4.0 to 8.4.1 and now I have the same issue on both router. So no problems on 8.4.0, but as soon as I upgrade to 8.4.1 the problem appears (and will not go away…).
You will probably say that I should not use 100Mbps anymore. You are right 
But I have an old media converter that converts Ethernet to fiber and back that uses an 100Mbps ethernet interface. I need fibre to cross a larger distance. Of course, I can replace those media converters to new 1Gbps versions, but that would also involve new fiber patch cables and will be quite costly.
So the question at hand is: why do 100Mbit connection fail on the WAN-port in combination with firmware 8.4.1? Is this maybe a known issue?
Kind regards,
John
