Auto Posting

I get a 200 error code when trying to auto post. This is the message from the company that does the autopost:

IMPORTANT!!! So we can post successfully to your blog, your hosting has to accept something called XML-RPC connections. It may also need to have our IP 107.173.57.119 'whitelisted'. Our system uses XML-RPC connections to your blog in order to be able to post articles and images for you.

If you're not sure about your hosting setup, please give this entire message to your hosting support and ask them to ensure that your site settings are correct for this. It's best to do that before you add a blog here.