I can't open any pdf since last week. I have a Samsung s6 edge with t-mobile. I spent an hour and a half with t-mobile tech support and they told me to email you because they don't know what else needs to be done.
May I know what happens when you are trying to open a PDF with Adobe Acrobat app on your Galaxy device.
Go to Settings > Apps > Adobe Acrobat
Under App Info, click on Clear Cache
Then try to open PDFs
Still if it is not working
Uninstall the app
Then download and install it from APK file directly.
Let me know if this works for you.