Green’s Dictionary of Slang

a failure, a disaster; often qualified as epic fail.

2012		C. Eble UNC-CH Campus Sl. 2011 4: FAIL — <failure ‘The event was a total fail. No one showed up.’.
2012		International Business Times 24 Jan. 🌐 [headline] McDonald’s #McDStories Twitter Campaign is an Epic Fail [...] the promotional campaign became an epic fail when countless tweets rolled in depicting horror stories ranging from finding a burger containing a finger nail to vomiting on site.