Galaxy Tab S4 shows drive empty

I have had this SanDisk Connect Wireless Media Drive for years and it’s worked beautifully on my old iPad.  Now I have a new Galaxy Tab S4 and have  downloaded the app.  But I have a heck of a time trying to connect to the drive saying it’s ‘trying to connect’, then when I am connected, showing ‘wifi disconnected’.  When I finally get to the drive, it shows that it’s empty even though I’ve got a number of movies on it.  Why am I unable to access what’s on this drive anymore?

what version of android is the tab running? the media drive is pretty old and no longer being manufactured. The app may not work with newer versions of android. 

The tablet is running 8.1 so you are probably correct.  Bummer.  That’s like having any sort of external memory device or chip  become inaccessible, and I’ve never had that happen before.  Guess I’ll have to pull everything off onto my hard drive then toss it.  Thanks.