Most common cause of the symptom
You have not got a PDF reader installed onto your Android device.
Some Android devices do not come with a PDF reader installed as standard and so you need to download a third party
1. Try downloading Adobe PDF Reader for your Android device:
Once installed try to open a PDF from Insite Teams and see if it gives you the option to open with Adobe Reader.
If it does not give you the option to open with Adobe try following these steps:
a. Go to settings -> Apps -> All
b. Scroll down to find the “Document viewer” app and tap on it
c. Scroll down to the “Launch by default” section and tap the “Clear defaults” button
Once you have completed the above steps head back to Insite and try to open a PDF. It should now give you a prompt to choose to open with Adobe.