Adobe Acrobat shows this error when S/MIME certificate has been used to digitally sign a PDF document. Adobe and Sectigo are offering a new product, specifically targeted for document signing. Citation from Sectigo Support:
Hello,
Greetings from Sectigo Support!
Yes, the Personal Authentication Certificate which you've purchased will give a trusted identity error when you sign Adobe PDF files. Instead, it is recommended to purchase a new certificate specifically designed for document signing which comes with a new trusted chain " Sectigo RSA Document Signing CA” added into Adobe Approved Trust List (AATL).
Please do refer the following link for more details about Sectigo document signing certificate.
https://sectigo.com/ssl-certificates/document-signing-certificates
Please let us know if you need any further support.
Regards,
Sectigo - Technical Support
Solution: kindly obtain a Sectigo Document Signing certificate (InterSSL is currently not offering this product).
