[Django]-Django-haystack autocomplete not working as it should

The RequestError you linked to indeed provides a useful hint.

You seem to be using ES 2.x and Haystack uses the _boost meta field which has been removed starting with ES 2.0.

You can see that there is an issue (#1247) about making Haystack work with ES 2.0 and it is still open.

What you can do at this point is either to install ES 1.7.5 instead and it will work.

Or wait until the fix gets released in a new Haystack version.