Why do attachments not work when app is published but does when in Studio?

[Mgodby]

I have an attachments object here in powerapps.

When I'm in studio I can successfully download the files. But when I publish the app and try to download a file, this happens.

What is going on here? Isn't studio supposed to simulate the app actually being published? Why does it work in studio but not when I publish the app? I remember this working fine a few days ago and I haven't changed anything since then, this just started happening out of nowhere. 

[Mgodby · Accepted solution]

noticed it was actually failing in studio too where the file was corrupted or empty. fixed it  by changing the "Value" property of the attachment.