Ah, the four horsemen of developer excuses! That moment when your client hits you with the dreaded "it doesn't work" with zero context, and you're suddenly on a game show with no lifelines.
The correct answer? All of the above, in rapid succession, followed by asking them to send a screenshot that will inevitably be a photo of their monitor taken with a potato.
After 15 years of coding, I've used every single one of these excuses. My personal favorite is "works on my machine" – the programmer's equivalent of "not my problem" but with just enough technical ambiguity to sound legitimate.