The best mechanics can track down an issue by reasoning about what could be causing it

Same principle works with IT. I do and have done sysadmin stuff for quite a while and there’s always some random software or whatever I’ve never heard of and someone comes and asks me to fix it. Then you start to ask questions, “what exactly doesn’t work”, “can you show me what you’re doing”, “what should happen when you press that button”, “can you show settings on that thing” and so on. Then you can start to dig down, does the server they’re using respond to ping, does DNS resolve (it’s always DNS after all), does that thing work on the next workstation, when did the problem appear and was there some other maintenance or changes going on at that time and so on.

Same principle, just start to reason the whole thing from bottom up, check everything you come across untill you find something which doesn’t work and then do what’s needed to fix that, rinse and repeat until the problem goes away and make sure that what you’re doing won’t cause new problems. Just the tools are different, the mindset is more or less the same.