Prevented empty messages from being sent and fixed a typo
Prevented empty messages from being sent and fixed a typo

cafe-grader-team/cafe-grader-web,nattee/cafe-grader-web,cafe-grader-team/cafe-grader-web,jittat/cafe-grader-web,cafe-grader-team/cafe-grader-web,nattee/cafe-grader-web,cafe-grader-team/cafe-grader-web,nattee/cafe-grader-web,jittat/cafe-grader-web,nattee/cafe-grader-web