Something was wildly wrong with the Server. CPU was maxing out and I was not able to access any database related stuff in spite of root access. I unfortunately had to restore the entire system from a 5 days old backup, meaning high-scores got lost. Sorry!! I must still add some fallback method to be able to restore the Database in case of further issues. But I have removed some code that might have been responsible and am monitoring the Server more frequently. CPU is hardly doing anything as should be expected from high-scores. What currently is no longer working: Seeing friends high-scores. This required me to check the friend-highscore-tables of steam and was possibly the cause of the whole problem. I will look into finding a solution to this, but not right now.