A: Check for digital signatures. A signed PDF is locked, but the jacket might still be editable. Remove the signature, flatten, then re-sign after submission (if required).

Before diving into solutions, let’s clarify what “jack or the submission pdf” could mean:

Before uploading, go to File > Properties > Remove Personal Information. Or use a PDF sanitizer. The phrase "jack or the submission PDF" is a reminder to clean both the visible content and the hidden jacket.