This is a situation you do not want to be in, as a business doesn’t function without its employees. Workers can feel discouraged by many different factors, whether it be personal, or work-related as everyone has their own battles.
There is no straight answer to this problem; however, start by going to each employee and build a bond with them. Understand how your team functions. Some workers need positive motivation, others a reality check. Are there any distractions or personal problems? Do they lack incentives?
Build a certain level of trust and understanding with them, so that the problem doesn’t repeat in the future, and if it does, you’re the first one to know.