Blender renders black screen[Help please]

im working on item for game,its all good. i wanted to do it fancy and show it in box and with some lightning. Through the work i was looking on fast render so i knew how it should look,but when i finnaly rendered it. all came out was black screen… dont know what happened. Everything was going well until finnal render,and i cant find solution. Can any kind person help me?

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