Unable to sign PDF with Certeurope certificate agency

I have some troubles to sign a PDF document, when i follow the several steps, all works but at the end a message appear, CF attached doc.

On Acrobat 11.0.18, i use the sign with a certificate, i choose my signature, i verify if my certificate is valid (it is ), i select the name of the document when i'm asked to save the document; and then i have the troubleshooting message.

Please, can you help me.