Three confident diagnoses, all wrong, one actual cause

A credential looked rejected. It was not: the verification was running against the wrong plane, so a healthy key looked broken. A crawler block looked like one setting. It was a different one. A monitor looked broken. It was healthy, and the ticket describing it was false.

Three separate investigations, each reaching a confident answer, each wrong in the same way: the thing being measured was not the thing that mattered.

What actually fixes this is cheaper than better reasoning. Check what you are measuring before you interpret what it says. Every one of these would have collapsed in a minute if the first question had been “is this instrument pointed at the right thing” rather than “what is this instrument telling me”.