Issue Summary

When a user tries to upload a big file to their card (e.g., a video file with 200MB in size) through their web browser, Trello will start the uploading process, and timeout, resulting on the upload not being completed. 

Steps to Reproduce

1. Open a card
2. Upload a big file to your card
3. You'll notice the "Uploading" banner on the left side never completes, and after some time, the browser throws a timeout error, as shown below
   

Expected Results

Any type of file regardless of their size should be uploaded to cards when using Trello on their browsers. 

Actual Results

Big files are timing out when being uploaded to cards, preventing users from taking advantage of their paid feature of 250MB file upload. 

Workaround

No workaround available at this time