Wordpress: tax_query multiple terms using OR operator
try adding array and make it like this :
$todo_args = array( 'cat' => $my_category_id, 'posts_per_page' => 1, 'tax_query' => array( 'relation' => 'OR', array( 'taxonomy' => 'postkicker', 'field' => 'slug', 'terms' => array('monthly-to-do-list'), ), array( 'taxonomy' => 'postkicker', 'field' => 'slug', 'terms' => array('community-events'), ), ), 'orderby' => 'date', 'order' => 'DESC');As you may notice terms is plural so you may also simplify your query like this :
$todo_args = array( 'cat' => $my_category_id, 'posts_per_page' => 1, 'tax_query' => array( array( 'taxonomy' => 'postkicker', 'field' => 'slug', 'terms' => array('monthly-to-do-list','community-events'), ), ), 'orderby' => 'date', 'order' => 'DESC');