What is Byzantine generals problem

Byzantine generals problem is a game theory states suppose you are attacking a fort for different sides, how can all the general in all sides of fort come to the consensus without a trusted central party that everyone will attack the fort at the same time. Only is attack happens at the same time they win else no

Let’s say, you pass message through soldier from your side with the time of the attack to the rest of the 3 sides, how do you know that message was reached, how do we know that message was not infiltrated in between. Let’s say you confirm if the message was reached only after getting a reply how do you know that the reply is legitimate? How can other general trusts the source etc

Byzantine general problems occurs onlt in decentralised world as there is no reliable source of information, in case on centralised system we trust central authority to report reliable information

This is an unsolved problem until bitcoin was created. Bitcoin claims to have solved this problem

How bitcoin solves this?

Proof of work -> Which is the core of bitcoin solves this problem.