Working out what is actually wrong.
WHAT TO ESTABLISH FIRST
What they observed, precisely.
WHY
Reports describe interpretations, not observations.
WHAT THAT MEANS
The site is down may mean an error page, a slow load, or a typo in the address.
WHAT QUESTIONS WORK
What exactly did you see? What were you doing immediately before? When did it last work? Does it happen every time? Does it happen for anyone else?
WHY THE LAST-WORKED QUESTION MATTERS MOST
It bounds the window in which something changed.
WHAT TO ASK ABOUT CHANGES
What changed on their side What changed on yours
WHY BOTH
Coincidence is common, and so is denial.
WHAT TO VERIFY YOURSELF
Whether you can reproduce it.
WHY
A problem you cannot reproduce is diagnosed by guesswork.
WHAT TO TRY IF YOU CANNOT
A different connection A different device Their exact steps, in order
WHAT TO CHECK IN YOUR OWN SYSTEMS
Logs at the time they reported Whether anything else changed then Whether other customers are affected
WHAT TO AVOID
Assuming the customer is mistaken Assuming the customer is correct
WHAT TO DO
Establish the facts, then explain them.
