« MODx Parse Error »

MODx encountered the following error while attempting to parse the requested resource:
« PHP Parse Error »
PHP error debug
  Error: date(): It is not safe to rely on the system's timezone settings. You are *required* to use the date.timezone setting or the date_default_timezone_set() function. In case you used any of those methods and you are still getting this warning, you most likely misspelled the timezone identifier. We selected the timezone 'UTC' for now, but please set date.timezone to select your timezone. 
  Error type/ Nr.: Warning - 2 
  File: /var/www/vhosts/qassim-alsaedy.com/httpdocs/assets/snippets/maxigallery/maxigallery.php 
  Line: 73 
  Line 73 source: $mgconfig['thumb_watermark_txt'] = (isset($thumb_watermark_txt)) ? $thumb_watermark_txt : "Copyright ".date("Y"); // [ text ]  
Parser timing
  MySQL: 0.0022 s(5 Requests)
  PHP: 0.0134 s 
  Total: 0.0156 s