You can filter “No Post Found” text by filter hook as follows.

add_action('post_grid_no_post_text', 'post_grid_no_post_text_20200614', 10);

function post_grid_no_post_text_20200614( $no_post_text){
    
    $no_post_text = __('Custom no post test', 'posy-grid');

    return $no_post_text;

}

Parameter:

  • Text

Screenshot: 

Post Grid Plugin post_grid_item_bottom