@jacek I'm assuming it means "invalid option"
@AskChip Actually it meant "I'll reject your, perfectly valid, host header and won't tell you more ;)".
Sending proper HTTP error code would make lifes easier.
@jacek It is a proper error code for invalid option requesting coffee. Not that you actually requested coffee. Some programmers get a little weird when their debugging takes too long.
@jacek It's a valid code from RFC 2324. 😋