After my computer broke down yesterday I have spent hours trying to find out the problem - no I am not a know-how. Anyway changed the cable from phone to router - no joy, tapped all the plugs on the router and on back of hard drive - no joy. Found a new router from years ago put plug in - no joy, tried the "plug" into another socket router started to light up TG. Put plug in another socket beside computer and low and behold I am back with yous all again. I maybe will think of taking "how to fix computers" next year. That's all folks!
You've performed the first aid approach which has fixed many electrical appliances.
If it was the electric plug (can't make it out in your post), many of the overseas products have some insulation over the prongs so it depends on what type of socket it is plugged into. The ethernet/phone plug is sometimes not pushed in properly - it should go in gently until you hear/feel a healthy click.