Avada is the most popular WordPress theme on the market. Unfortunately it doesn’t work with Relevanssi out of the box. The reason for the incompatibility is the most common there is: there’s an unnecessary
query_posts() call in the search.php file. To make Relevanssi work, make the following change to the search.php file. Find this line:
And either remove it or comment it out (by adding // in front of the line). Since an update will overrun any changes you’ve made, this is best done in a child theme.
Update 2.7.2015: Looks like Avada is compatible with Relevanssi from version 2.8 on (approximately).
Update 11.1.2016: Avada 3.8.4 should work without problems with Relevanssi.
Update 19.1.2016: Avada 3.9.1 should work without problems with Relevanssi.