Whenever I try to log on to my account on my computer, I get this message. I looked it up, and apparently it happens sometimes, so I was hoping someone on here could help. When I was looking for a solution online, there were different ways to fix it, but most were a bit complex or I didn't quite understand what they meant. I'm pretty good with computers, but not entirely familiar with them, so I'm looking for the easiest (if there is one) and/or safest way to fix this. Also, an explanation why this might have happened and maybe how to prevent it in the future (if I can).

There are some ways to fix it. There is the method of the back door. I need to now your OS.

The problem was fixed by a friend of mine. (Thanks Aiir for offering help)