Hello Afif, the JSS calculation primarily depends on the client's Private Feedback. I believe that one or more of your clients gave you bad Private Feedback. obviously, you have got bad Private Feedback about the cancelled contract. This might explain the drop in your JSS.
PS: Once you have a contract with a client. The client can give you Private Feedback whatever no matter what, even if the contract was cancelled.
For now, try to get more successful contracts done, and your JSS will improve over time.
Wish you the best,
Youssef
