Moved server and feeds now showing raw shortcode

Have this working pretty much flawlessly on development site using the shortcode but moved the site onto its live server and now the feeds have disappeared, replaced simply with the shortcode.

I had to deactivate plugins to get the site working, but on reactivation this has occurred. Am I missing something obvious, or is it a cache issue and the feeds will start appearing again in time?

https://wordpress.org/plugins/wp-rss-multi-importer/