JDBC Connection fails on long upload

1. Log in to Zanata with Google Chrome
2. Go to a project version
3. Click Settings, then Documents, then +
4. Throttle:

• Press Ctrl+Shift+J to bring up the browser console

• Click Network

• Click No Throttling

• Click Custom -> Add -> Add Custom Profile

• Enter a name (e.g. modem 28k) with 28 up, 28 down, 100 latency, click Add, click the x

• Select modem 28k

5. Click Browse and select a file of about 4-5MB
6. Click Upload
7. Wait

Expected:
File is uploaded

Actual:
Internal server error