Issue Summary

Previews on audio attachments dating 4-5 years back don't work and throw the "There is no preview available for this attachment" error message. 

Downloading the audio file to a local machine allows it to be played successfully. Also, re-uploading an audio file to the same Trello card brings up a preview.

Steps to Reproduce

1. Find a card where an audio file was attached a long time ago (more than a year)
2. Try to open the file preview 

Expected Results

The audio can be played within Trello. 

Actual Results

The "There is no preview available for this attachment" is shown and the file needs to be downloaded to play it. 

Workaround

Download the file and upload it to the same Trello card again.