no output from getTweets() call

I’ve installed the plugin and created the relevant keys and tokens and placed the call in a template. However it doesn’t retrieve any tweets and nor do any debug errors appear in the log on the settings page. I’ve tried it on my testing and production enviroments and still get the same result. There must something I’m doing wrong but I can’t seem to work it out.

https://www.ads-software.com/extend/plugins/oauth-twitter-feed-for-developers/