So, I tried to get a security key for my acc, but after typing the serial code in the app it works, though the security key i put on the browser doesnt work. After clicking save it says "serial code incorrect. Try again." Any help?

the browsers wont save the security key and you need to type in that each time you log into the game and browser, once you use the first set of digits in the security key you wont be able to use them again.

What I'm saying is that I get the serial number, but that in the app, the app generates the key, but when I put the key in the box and hit save it says "wrong serial number"

 

which means the serial number is broke..?

Check the date and time is 100% correct on the mobile

 

You can use Win Auth on the PC as well per link

I just tried to do this and get the security code from the app every few seconds but when i put it into the website it says "Sorry we couldn't find your serial number. Try again?"