Can´t Sign confidential documents

When a document is labeled Confidential with encryption in Microsoft Purview, it becomes RMS‑protected. This means the file is encrypted and can only be opened by users who have explicit permissions.

Because of that, external tools like DocuSign cannot decrypt or modify the file. They need full access to inject signing fields and apply the digital signature, so the signing process simply won’t work on an encrypted document.

The only workable approach today is to temporarily remove or downgrade the label (to a non‑encrypted version) before sending the file for signing. After the customer signs it, you can re‑apply the confidential/encrypted label again for storage and compliance.

Hope this helps :)