This is not really the Central Powers but more Germany who were part of the Central Powers and thus can be noted as a failure of the Central Powers. At first we know that Austria-Hungary declared war on Serbia as a result of the assassination of the Archduke Franz Ferdinand. It later escalated to Russia and Germany joining the war.
Germany by themselves with the mistakes they had made arguably caused the downfall for the Central Powers. As there plan to quickly eliminate France in order to focus on Russia later(they planned on beating France first and leaving Russia alone), they wanted to ‘passively’ go through Belgium. This would allow them to bypass the Maginot Line - the border between Germany and France which was heavily fortified by France. This border would have taken Germany a tremendous amount of effort and time to breakthrough which would have not allowed them to defeat France in time. So in theory this would have been the right move even if Belgium resisted right? Wrong. You see the Kaiser and his generals did not think this one through enough.
Belgium was in a alliance with Britain. And Britain at this time did not want to go to war with Germany. This meant that when Germany did invade Belgium, as part of their treaty Britain also declared war and even warned Germany about this. The Kaiser was surprised about this but nonetheless carried on. Everything basically went wrong for Germany in this plan. Belgium resisted and burned infrastructure slowing down the Germans. Furthermore and ultimately, it took long for the invasion of France that Russia mobilized their army and invaded which the Germans again didn’t anticipate. This lead to Germany sending troops from the west to the east further weakening their invasion against the Germans.
So from this we see that the Germans arguably caused Britain’s very early entry into the war and furthermore as the aggressors could have been to blame for the war (which the Treaty of Versailles Article 231 took advantage of). I did not include Germany provoking America as America did not have too much of an impact(due to their very late entry - the war was already won and almost over by that time).
Of course their were other mistakes made which hurt the Central Powers and Germany such as thinking the British were inferior and paying for it but I believe Germany being the aggressors and invading Belgium was their biggest mistake even though they did not know.
