how nerdy are you and do you have a Mac or windows? There’s some command line stuff we could do test stuff.
A few other things:
when changing routers did your ssid and/or password change?
And, I assume going to apexfusion.com doesn’t give you access. If that correct?
can you login to the routers ui? Most/all will give you a list of connected devices. Check there to see if the apex is listed and what the IP is if it’s indeed connected. You can find out how by googling “(router-name) show connected devices” or something similar.
My first goal would be to see if the apex is on the local network or not.
Checking the router would be the easiest way as it will tell you the IP if it is. If you see it in that list point your browser to
http://192.168.1.10 (replace that made up IP with whatever the router says it is).
my apex is listed as "IEEE Registration Authority" but it could be anything. Might be easier to check everything (go to http://<ip_address_here>) who's name you don't recognize (some stuff will be obvious like "iPhone" or "Playstation" etc).
If you've tried everything in the list and still haven't found it then hard wire the apex to the router and check again.
If you still don’t see it call Neptune support.