What model modem do you have? You said you reset the modem via the app, which makes me think you are using a Panoramic gateway. If so, do you have it in bridge mode? Also, does the problem happen if you connect direct to the modem?
Also, when you say "Cox wifi" do you mean the network name(SSID) called "CoxWifi" or just your wireless connection from the Orbi? The reason why that is important is CoxWifi is the SSID for Cox's hotspot. That's the network that Panoramic gateways and AP on the pole broadcast so you can get online when away from home.
One thing you can try is change the DNS on your Orbi. See here on how. Instead of the DNS servers in that article though, use google's DNS which is 8.8.8.8 and 8.8.4.4.
Last, try accessing from a VPN. Opera GX has a free VPN built into their browser you could test with.