@Vincent-TP 

The problem is that it was never eligible for adoption. So no, I haven't.

  @MR.S 

Both are 255.255.255.0, so I guess setting it back to factory is the only option left then. Whenever I performed this, I will update here.

  @Dacruzzz 

I think it's easier if you show a screenshot

  @MR.S 

Sure no problem, which info do you want to see?

  @Dacruzzz 

we write a bit at the same time here so the thread got a bit messy :-)
try a factory reset first and see what happens. do not do any settings or configurations, just wait for the router to appear in the controller,

  @Dacruzzz 

fantastic, then you get to enjoy yourself with the new ER706W, WiFi has an incredible range and is fast, but remember to choose EAP and gateway when you create the SSID, otherwise WIFi won't work on this router,

  @MR.S 

Thank you for your reply.

This was already set-up in the controller and the ER706w adopted these settings immediately. So the WiFi was good from the get-go.