Hi, and I hope someone can help me out. I'm running an ASUS RT-AC86U stock firmware, version 3.0.0.4.382_18219 (I don't think that I need a different firmware like dd-wrt for this, right?) and I have a Fios gigabit connection and I do get about 950 down/900 up speeds.

I'm attempting to run in Dual WAN mode with my Samsung Galaxy S8 tethered as the failover. The GUI shows both of the WAN connections. I'm running DHCP to handle IP assignment within the LAN and I'm defaulting to the WAN's DNS server(s) by leaving those fields blank and Verizon and T-Mobile use different DNS' I also have QoS turned off and both my IPv4 and IPv6 firewalls are off, temporarily.

I've tested the failover by either removing the FIOS cable from the wan port, and by making the USB connection primary and it works, kind of...

My issue is that my download speed over Cat 7 cable when the phone takes over are around .05Mbps which makes the connection all but useless while upload speeds remain where they should be at 28Mbps.

I have unlimited 4G LTE hotspot and tethering through T-Mobile (ONE plus international), so I know they're not throttling me (I've used < 5 GB this cycle) and to confirm this, I unplugged the ethernet cable from my PC and tethered the phone directly to my laptop with my WiFi turned off, so the phone was the only source of internet. Speedtest.net showed 66.97 down and 26.23 up which is right about where it should be.

Does anyone have any idea as to what could be throttling my DL speeds at the router?

Thanks in advance!