How to protect the router or what could cause the WAN port on the router to burn out?

Question

network hardware

Good afternoon!
I have such a broken patient as in the photo. I loved and liked the router very much, as well as the appearance, and it worked properly without problems. The problems started suddenly and completely out of the blue. I went to the store for half an hour - there was no Internet back. After a couple of hours of torment: reboots, reset buttons, flashing, calls to the provider and consultations with the search engine, I realized that my router port burned out. However, nowhere is there really a good and understandable article about the causes of this incident or about recommendations for protecting against such a problem in the future, which is why I am turning to you for a little recommendation.

router

The following questions are of concern:
1. Why did the port burn down? (I saw mentions on the toaster about a thunderstorm, but I didn’t have a thunderstorm at that moment, I went to the store)
2. How to protect the new router from burning the port?
My router stood vertically (face down so as not to take up space on the table), and not as it should be, as in the picture. I don’t know if this could somehow affect))
I would be very glad for valuable tips or a good post on this topic, because I haven't been able to find a good answer anywhere on the internet for this.

Answer 1

1 most likely from a voltage drop, the cause of the drop is already the tenth thing - a thunderstorm or something else.
2 lightning protection is needed, IMPORTANT - it does not work without grounding.