Hi DamienGTL,
Can you see a permission prompt message when you open these documents? If so, this usually means the documents has been set specific permissions, you got the folder open permission but didn't got the files open permission. You can consult the sender to check if these documents have specific permissions for you. Share the specific file again separately with you, and see the result.
If you see the file loading forever or a blank page, I would like to suggest you copy the link and open it in another browser to see the outcomes, you can also try to use the browser private mode to open the link. Besides, check your network environment, switch to another network if it's available for you, close the proxy or firewall temporarily to open the link again.
If you get other types of error message, could you provide a screenshot of the detailed information? And, does the issue happen to all files inside that folder?
Best Regards,
Hugo