Unable to connect after initial setup

Good morning folks,

I picked up the KHD and set it up Friday evening via the iPhone app. Everything went slowly, but I got it calibrated, ran a test with a very high result, then set it to test 8 times daily. I attempted to connect it to my Wifi but it wouldn't connect and I never lost connection using the built in hotspot, though it was always very painfully slow.

In the morning, I connected via the app and saw that my latest result was 7.2 dKH, spot on with my manual testing. I couldn't see any history because I never got it to connect to the Internet. I then tried using GHL Control Center with my laptop via USB without success. I had to download the proper drivers and changed the port setting to auto before connecting.

I then used my phone to connect to the hotspot and tried changing the Wifi one more time. I set the IP address to 192.168.1.91, the subnet mask to 255.255.255.0, and the default gateway to 192.168.1.1. That was the last time I could connect in any manner.

This morning, I connected it via Ethernet cable directly to my router. There was a solid yellow (?) light by the port both before and after plugging in the cable. The other light never did anything. My router's indicator lights don't light up as they do when it detects a connected device. I checked my network in my router's menu and can't find the device. I swapped the cable to connect my modem and router and it worked well at full internet speed.

After checking all of these things, I'm at a loss. What are my next steps? I'm no IT guy, but have poked around networks enough to have a basic knowledge of how to get around from back in the days of port forwarding to connect my Apex with Reeftronics in the pre-Fusion days.

Thanks for any help.