These links are being provided as a convenience and for informational purposes only; they do not constitute an endorsement or an approval by [The author] of any of the products, services or opinions of the corporation or organization or individual. [The author] bears no responsibility for the accuracy, legality or content of the external site or for that of subsequent links. Contact the external site for answers to questions regarding its content.
If clients are not able to view PDF files in Chrome, they most likely disabled them. I have attached two articles that will help with this below, the first is how they most likely caused this to occur, the second includes steps on how they would be able to try to re-enable them.
How it occurred:
How to fix it: