Using Mozilla Firefox is the best solution for reading the ID card.
If the PDF does not open in Adobe Acrobat Reader, you have to make the association of the file type again
This message indicates that Acrobat Reader does not recognize the FPS Finance certificate that is listed in the document.
This does not block the signature, you can ignore this message and scroll down the document to click on the declarant's signature box.
=> Execute the second step of the following procedure again: PDF signature