Protocol negotiation failed

[LittleTin]

I have 2 NIC, first is connect with router, second is connect the Modem.
I always use second NIC and use pppoe get real ip, first NIC is a backup connection, if pppoe disconnected, it can let me keep-alive.
but today have big problem, I cannot remote my pc.
If I use pppoe, it will show "Protocol negotiation failed".
But I turn off the pppoe connection, use first NIC backup line, my pc can be connected.
And I try again pppoe to get real ip, use that ip connect teamviewer, my pc can be connected, too.
I have been reinstall, clean registry, delete all teamviewer files in my HDD but no effect.

OS:Windows 8.1, Teamviewer 11

[matt]

So this is the remote machine that you are trying to connect to that has the 2 NICs?

Why are you PPPOEing to a modem? Normally the modem would do the PPPOE to your ISP, or your would bridge the modem and connect PPPOE to the ISP using the bridge
Did I miss something??