I used to moderate here, and I can’t see much wrong with your comment; I suppose someone might have considered it off-topic. But other things can happen to comments. If it was a reply to another comment that was deleted, it will have become collateral damage. If it disappeared immediately upon posting as opposed to appearing and then disappearing later, the spam filter probably ate it, in which case I’d suspect the link. Or it could have been deleted by mistake. Personally I’d try posting it again without the link, and if that comment appears I’d try adding the link as a reply to it, possibly omitting ?INPCMP= and everything to the right of it.