MinimongoError: The positional operator did not find the match needed from the query

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MinimongoError: The positional operator did not find the match needed from the query
this error when i build and Run it with PM2 and Mongo

   progress[userIndex].userId = course.userId
            progress[userIndex].units[unitIndex].unitId = course.unitId
            progress[userIndex].units[unitIndex].isLast = course.isLast
            progress[userIndex].units[unitIndex].isQuiz = course.isQuiz
            progress[userIndex].units[unitIndex].isFinalQuiz = course.isFinalQuiz
            progress[userIndex].units[unitIndex].questions = course.questions
            progress[userIndex].units[unitIndex].at = new Date()
      
            console.log("progress", progress)
            return Courses.update({
                _id: course.courseId
            }, {
                $set: {
                    users: progress
                }
            })