Not every application will be successful, as Immigrations has tightened the criteria for the S Pass to raise the overall quality of the foreign workforce. There could be multiple reasons for this. However, all is not lost, You have 3 months to appeal an unsuccessful S Pass application, but you should do so only if you can address the reasons for rejection. If you miss this time period, you will have to submit a new application.
You can check the rejection advisory in EP Online to view the reasons for rejection and get advice on what to do next. If you applied manually, check the rejection letter. To proceed with the submission for appeals, do note that only the employer or the authorised third party who submitted the application can do so.
Appeals are usually processed within 3 weeks, and you can always log in to EP Online to check your appeal status.