Warning: mysqli_connect(): (28000/1045): Access denied for user 'piwik'@'localhost' (using password: YES) in /var/www/html/piwik/core/Tracker/Db/Mysqli.php on line 76

Fatal error: Uncaught exception 'Exception' with message 'Connect failed: Access denied for user 'piwik'@'localhost' (using password: YES)' in /var/www/html/piwik/core/Tracker/Db/Mysqli.php:79
Stack trace:
#0 /var/www/html/piwik/core/Tracker.php(175): Piwik_Tracker_Db_Mysqli->connect()
#1 /var/www/html/piwik/core/Tracker.php(191): Piwik_Tracker::connectPiwikTrackerDb()
#2 /var/www/html/piwik/core/Tracker.php(63): Piwik_Tracker::connectDatabase()
#3 /var/www/html/piwik/piwik.php(74): Piwik_Tracker->main()
#4 {main}
  thrown in /var/www/html/piwik/core/Tracker/Db/Mysqli.php on line 79