The message sometimes is "undefined" when upload failed

[harrynull]

Are you submitting a bug report?

Yes

Steps to reproduce

1. Go to http://www.getwox.com/plugin/create
2. Fill in all the required information, with more than 2000 characters in description.
3. Click submit
4. A message saying "undefined" pops up. The response from server is:

{"long_description": ["Ensure this value has at most 2000 characters (it has 2255)."]}

Wox Error Window text

N/A

Detailed logs

N/A

Screenshots (optional)