That's not what the log says. OBS is using your 802.11n wireless adapter:
12:21:26.312: [rtmp stream: 'adv_stream'] Connecting to RTMP URL rtmps://rtmp-api.facebook.com:443/rtmp/...
12:21:26.376: [rtmp stream: 'adv_stream'] Interface: Broadcom 802.11n Network Adapter (802.11, 137 mbps)
12:21:27.716: [rtmp stream: 'adv_stream'] Connection to rtmps://rtmp-api.facebook.com:443/rtmp/ successful
Go to Windows networking and change the adapter settings. Disable the wireless adapter and enable the Ethernet.