"Modifying placeholder details is not allowed in this signature request."

Summary

When a user sends a Box Sign request from a reusable template that has Signature & Fields locked, and they replace the document before sending, Box Sign may fail with an error that placeholder details cannot be modified.

Symptoms

Users may get the following error message when they select Send:

Modifying placeholder details is not allowed in this signature request.

Common reproduction pattern:

1. Create a reusable Box Sign template.
2. Place signature, date, stamp, or other fields on the document.
3. Lock Signature & Fields (so template users cannot change field layout).
4. Share the template with another user (for example, Viewer access).
5. That user selects Use template, replaces the file (often with Keep existing fields), fills recipients, and sends.
6. Send fails with one of the errors above.

Root cause

Box Sign treats locked Signature & Fields as non-modifiable. When a template user replaces the source file before send, Box Sign may attempt to rebind or adjust placeholder positions for the new document. That adjustment conflicts with the lock, and send is rejected with the placeholder-details error.

This is more likely when locked fields are combined with file replace, especially when:

• Fields sit very close to the page edge, and/or
• The replacement file uses a different page orientation than the template file (for example, portrait template file replaced with a landscape PDF).

Resolution steps

Try these mitigations in order.

1. Unlock Signature & Fields on the template, save the template, use the template again, replace the file if needed, and resend.
2. Move fields away from the page edge in the template (especially signature, stamp, and date fields near the top or bottom), save, then retry use → replace → send with the lock still enabled if required.
3. Keep page orientation consistent when replacing the file. If the template document is portrait, replace it with another portrait file (same for landscape).
4. Avoid file replace when Signature & Fields must stay locked. Send using the template’s original file, or create a separate template for each document layout.
5. If replace is required and fields must stay locked, create a new template from the target document with fields placed for that layout, then lock Signature & Fields.

If the error continues after unlock, same-orientation replace, and moving fields off the page edge, collect the following information and contact Box Support for assistance.

• Exact error text and screenshot
• Whether Signature & Fields is locked
• Whether file replace was used, and whether Keep existing fields was on
• Template file orientation vs replacement file orientation
• Network logs while reproducing the issue