Loading an App from email attachment

[AC Question]

G'day,
Unable to get the App, attached to an email to load. All ok with my other tablet, but with the PROTAB 7 all I get is a quick flash screen when I select the attachment.
Have enabled "Unknown Sources" and the main difference between the two tablets is the Android Version
Working tablet has 4.2.2 while the new PROTAB 7 is 5.1.1
Any ideas..

 

[anon(632115)]

You will need a file manager to install the app. Try astro on playstore