Can't connect to MySQL hosted at AWS

[wirecreative]

Hi, I'm running some preliminary experiments trying to find the right solution for a new client. They're going to have a large custom database that loads only on a few pages, so I thought it would be best to host that separately from the main Joomla database at their webhost. I created a MySQL database over at AWS and made it public (by following tutorials like this one). However, after setting up a Fabrik connection to this remote MySQL instance, I get "Unable to connect" messages.

Anyone have experience with connection Fabrik to an AWS-hosted db and know which hoops need jumping through to make it work?

Thanks.