USB Tethering stopped on GL-MT300N-V2

I easily got USB tethering working from my v3.102 when I first attached my Samsung Galaxy Core Prime.

But after power cycling the MT300, the MT300 reports it is connected to a 3G/4G modem and fails to connect to it:

[ 5143.465930] rndis_host 1-1:1.0 usb0: unregister ‘rndis_host’ usb-101c0000.ehci-1, RNDIS device
[ 5143.940180] usb 1-1: new high-speed USB device number 10 using ehci-platform
[ 5144.156720] cdc_acm 1-1:1.1: ttyACM0: USB ACM device

I have upgraded to V1.104 with no improvement.

The MT300 recognizes my iPhoneX and I am prompted on my iPhone to trust the MT300, but the MT has never successfully connected to it. The iPhone is identified as ‘eth1’ and pressing ‘connect’ just times out.
Of course the iPhone has no problem being USB tethered to my Mac.

Can you provide a more complete log?
I want to know what the router does when you click on the connection

Thanks for your attention.
I have repurposed the MT300 to another application where I have encountered a port forwarding problem which I have posted to another forum thread.
I will purchase another MT300 and continue this thread once it arrives.