Steps to reproduce:
2. Click on "New Mail" to compose a new email.
3. Click on the "Attachment" button and upload a valid electronically signed PDF using the "Drag-drop / Attach from your computer" option.
4. Fill in the recipient's email address, subject, and email body.
5. Send the email.
6. Download the PDF from the Sent folder or the recipient's email.
7. Verify the signature of the downloaded PDF and observe that the signature is invalid.
Expected result:
The signature of the attached PDF should remain valid when sent via Zoho Mail.
Additional information:
When the PDF file is archived, such as in a ZIP file, the file remains unaltered and the signature remains valid.