Hey, not sure if this is the right place to post this but I could use the help!

So since yesterday my internet connection suddenly stopped working. After testing a lot of things it seems like something is wrong with my wan port. This router have been working for 3-4 years I guess. Everytime I plug the cable from my modem to my router it just says something like: "searching for internet connection".
The LAN ports are working because I can still use the router as a switch. I'm just not sure if my WAN port is really dead or my modem is blocking something when I connect the cable to the WAN port.

I also checked all the cables and they all seems to work when I plug them into my laptop. I'm going to test with another router soon but if that won't work I could really use some help/tips. Anyway thanks for reading!