Warning: [mysql error 145] Table './abbaye/piwigo_sessions' is marked as crashed and should be repaired

SELECT data
  FROM piwigo_sessions
  WHERE id = '035Bgid25m3ni7tru0v1stmqg2n4q2'
; in /var/www/vhosts/total-mambo.net/abbaye/include/dblayer/functions_mysqli.inc.php on line 830
Fatal error: Uncaught exception 'Exception' with message 'DateTime::__construct(): 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 'Europe/Berlin' for 'CET/1.0/no DST' instead' in /var/www/vhosts/total-mambo.net/abbaye/include/functions.inc.php:584 Stack trace: #0 /var/www/vhosts/total-mambo.net/abbaye/include/functions.inc.php(584): DateTime->__construct() #1 /var/www/vhosts/total-mambo.net/abbaye/include/functions.inc.php(605): str2DateTime('2016-01-31 19:0...', NULL) #2 /var/www/vhosts/total-mambo.net/abbaye/picture.php(846): format_date('2016-01-31 19:0...') #3 {main} thrown in /var/www/vhosts/total-mambo.net/abbaye/include/functions.inc.php on line 584
Warning: [mysql error 145] Table './abbaye/piwigo_sessions' is marked as crashed and should be repaired

REPLACE INTO piwigo_sessions
  (id,data,expiration)
  VALUES('035Bgid25m3ni7tru0v1stmqg2n4q2','pwg_device|s:7:\"desktop\";pwg_mobile_theme|b:0;pwg_referer_image_id|s:1:\"4\";',now())
; in /var/www/vhosts/total-mambo.net/abbaye/include/dblayer/functions_mysqli.inc.php on line 830