Unfortunately, it's unlikely that you can upload your EWS certificate after completing the APICET registration. The registration process typically has specific deadlines for document submission.

However, it's advisable to contact the APICET helpline immediately. They might be able to provide guidance on your specific situation or if there's a correction window open.

Be prepared to explain your situation clearly and provide necessary documents. If there's a chance to rectify the issue, the helpline will guide you through the process.

It's crucial to act promptly as delays might affect your application status.

hope this helps you!!