Generally in situations like this, you should write down what everyone has told you. See if there's any consensus. Then set that aside and measure things and inspect how things are done. Talk and hearsay is great but measurements (actual data) is reality. It's a puzzle for you. Sometimes even a quick look at what people are doing, or their machines, or even setup, gives a clue or two. It's a trial by fire to troubleshoot, but it's quite rewarding to get to the answer quickly. Take all the information in, but don't necessarily buy into everyone's answers. It's usually a simple thing but it's obscured by the situation or someone's ego. Good luck!