my employment visa is reject due to security...

Please note that any transaction in the country, whatever its nature, including the visa application, needs security approval, say approval to issue a decision of approval or rejection, and the security rejection does not allow any party to know its reasons, but you can only try to re-apply for the visa application in another emirate in the same country and if it is done Approval: It is possible to work in any of its emirates without any legal obstacles