Warning: Constant WP_ALLOW_MULTISITE already defined in /var/www/html/wp-config.php on line 138

Warning: require_once(/var/www/html/wp-content/plugins/Mercator/sunrise.php): Failed to open stream: No such file or directory in /var/www/html/wp-content/sunrise.php on line 2

Fatal error: Uncaught Error: Failed opening required '/var/www/html/wp-content/plugins/Mercator/sunrise.php' (include_path='.:/usr/local/lib/php') in /var/www/html/wp-content/sunrise.php:2
Stack trace:
#0 /var/www/html/wp-includes/ms-settings.php(52): include_once()
#1 /var/www/html/wp-settings.php(157): require('/var/www/html/w...')
#2 /var/www/html/wp-config.php(155): require_once('/var/www/html/w...')
#3 /var/www/html/wp-load.php(50): require_once('/var/www/html/w...')
#4 /var/www/html/wp-blog-header.php(13): require_once('/var/www/html/w...')
#5 /var/www/html/index.php(17): require('/var/www/html/w...')
#6 {main}
  thrown in /var/www/html/wp-content/sunrise.php on line 2