"No!" you say, "I am on a quest! You cannot stop me, I am a good knight!"
"Yeah, yeah, whatever," says the gatekeeper, "heard it all before, shoo!" He then shuts the drawbridge fully, turns his stereo up and ignores you. Rather stumped by this, you sit there for a while, looking silly. Eventually, driven by numbing despair at your inability even to enter the kingdom, you attempt to gain entry by force. This is a fairly tricky proposition, given the equipment at your disposal. Attempting to wade the moat left you with nought but a slight chill, acute armour rash and a lot of rust. A bit of long range smiting with thrown pebbles leaves you with a sore throwing arm, though you realise that after you have thrown enough stones you will have filled the moat, solving that problem. A simple back of the armoured gauntlet calculation shows this will take many centuries, however, by which time someone else will have saved the kingdom. Giving it up as a bad job, you give up and, and bugger off back home. You find however, that in your absence, hyperinflation caused by the uncertainty in foreign markets has made your fortune worthless, and you are a pauper, so you throw yourself at the mercy of you now King brother, who spit roasts you.
I'd call that a failure, but I'd urge you to draw your own conclusions.