Why a certain URL ( a category URL ) disappears?

[mohamadalieskandariii]

the page hasn't been spammed. - links are natural - onpage grader is  perfect - there are useful high ranking articles linking to the page...pretty much everything is okay.....also all of my websites pages are okay and none of them has disappeared only this one ( the most important category of my site. )

[RossKernez]

Hi there,

I just want to be clear here. Do you mean that some of the categories were deindexed by Google?

Ross