Have you tried making that file available offline and seeing if it makes a difference?
If you email it to yourself can you open it on your phone?
I've had a similar problem and it was solved by downloading and installing the standalone version of Adobe PDF Reader DC from rocketfiles.com. Also, try to open the same file using the Dropbox website or open it with the desktop tool. Do not forget to close the VPN. Sometimes the problems may occur because of such IP changes-manipulations.
I have the same issue and this workaround does not work for me.
Cannot view any PDF, word, or powerpoint files.
Hey @wenhaoli, thanks for joining the discussion here!
So I can have a better understanding of exactly what's happening, can you send me a screenshot of what you see when trying to view the file within the Dropbox app?
Can you try changing to another WiFi or cellular data network and see if you still have the same issue?
Finally, are you able to preview these files via the website?
If anyone else here is also still having this issue, please get back to me here too with what you find to the above questions.
Let me know what you find!