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<b>Warning</b>:  mysqli_get_server_info() expects parameter 1 to be mysqli, null given in <b>/var/www/vhosts/dsa.gr/httpdocs/includes/database.mysqli.inc</b> on line <b>47</b><br />
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<b>Warning</b>:  mysqli_real_escape_string() expects parameter 1 to be mysqli, null given in <b>/var/www/vhosts/dsa.gr/httpdocs/includes/database.mysqli.inc</b> on line <b>417</b><br />
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<b>Warning</b>:  mysqli_query() expects parameter 1 to be mysqli, null given in <b>/var/www/vhosts/dsa.gr/httpdocs/includes/database.mysqli.inc</b> on line <b>149</b><br />
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<b>Warning</b>:  mysqli_errno() expects parameter 1 to be mysqli, null given in <b>/var/www/vhosts/dsa.gr/httpdocs/includes/database.mysqli.inc</b> on line <b>170</b><br />
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<b>Fatal error</b>:  Uncaught Error: Call to undefined function user_is_anonymous() in /var/www/vhosts/dsa.gr/httpdocs/includes/common.inc:2274
Stack trace:
#0 /var/www/vhosts/dsa.gr/httpdocs/includes/theme.inc(159): drupal_add_js('sites/all/theme...', 'theme')
#1 /var/www/vhosts/dsa.gr/httpdocs/includes/theme.maintenance.inc(63): _init_theme(Object(stdClass), Array, '_theme_load_off...')
#2 /var/www/vhosts/dsa.gr/httpdocs/includes/bootstrap.inc(1682): _drupal_maintenance_theme()
#3 /var/www/vhosts/dsa.gr/httpdocs/includes/database.inc(511): drupal_maintenance_theme()
#4 /var/www/vhosts/dsa.gr/httpdocs/includes/database.mysqli.inc(78): _db_error_page('Connection refu...')
#5 /var/www/vhosts/dsa.gr/httpdocs/includes/database.inc(478): db_connect(Array)
#6 /var/www/vhosts/dsa.gr/httpdocs/includes/bootstrap.inc(1552): db_set_active()
#7 /var/www/vhosts/dsa.gr/httpdocs/includes/bootstrap.inc(1481): _drupal_bootstrap(2)
#8 /var/www/vhosts/dsa.gr/httpdocs/index.php(14): drupal_bootstrap(8)
#9 {main}
  thrown in <b>/var/www/vhosts/dsa.gr/httpdocs/includes/common.inc</b> on line <b>2274</b><br />