Why does the Internet disappear via TP-Link TD-W8951ND?

It all started with a yellow spot on the router, but I blew it off. It’s been half a year. I started to lose connection with the Internet. I went to 192.168.1.1 and went to System Log and saw this:

8/6/2017 16:41:47> bridge only stop
8/6/2017 16:41:47> SNMP TRAP 3: link up
8/6/2017 16:41:47> Quick bridge not allow multi-channel

8/6/2017 16:41:53> SNMP TRAP 3: link up
8/6/2017 16:41:53> netMakeChannDial: err=-3000

8/6/2017 16:41:53> Last errorlog repeat 8 Times
8/6/2017 16:41:53> Accept() fail
8/6/2017 16:41:53> Accept() fail
8/6/2017 16:41:53> netMakeChannDial: err=-3000 rn_p=804d2bec

8/6/2017 16:42:25> Last errorlog repeat 136 Times
8/6/2017 16:42:25> Call Failed
8/6/2017 16:42:25> Last errorlog repeat 1 Times
8/6/2017 16:42:25> netMakeChannDial: err=-3000 rn_p=804d2bec
8/6/2017 16:42:29> Last errorlog repeat 9 Times.

Firmware version: 5.0.0 Build 140321 Rel.27294
Router Model: TD-W8951ND

Response

Is there a yellow stain on the router body? Is it from overheating, did something get burned?

I’m not very good at reading these router logs, it’s to TP-Link support. But I can say that if the router firmware is updated, a reset is done, and it is properly configured (and most likely it is configured correctly, because it used to work), and the Internet disappears, it is most likely a hardware failure.

Well, it would be good to connect the Internet directly to the computer, check. To rule out problems at the ISP.