Nefunkční web-error

Dobrý den,

nefungují nám stránky, nemůžu ani do adminu, píše to pouze toto (viz. níže) jedna se o domenu pernikovka.com, prosím, můžete to opravit?

Fatal error: Uncaught Error: Call to undefined function trailingslashit() in /data/web/virtuals/266053/virtual/www/domains/pernikovka.com/wp-includes/class-wp-textdomain-registry.php:103 Stack trace: #0 /data/web/virtuals/266053/virtual/www/domains/pernikovka.com/wp-includes/l10n.php(784): WP_Textdomain_Registry->set(‚default‘, ‚cs_CZ‘, ‚/data/web/virtu…‘) #1 /data/web/virtuals/266053/virtual/www/domains/pernikovka.com/wp-includes/load.php(1401): load_textdomain(‚default‘, ‚/data/web/virtu…‘, ‚cs_CZ‘) #2 /data/web/virtuals/266053/virtual/www/domains/pernikovka.com/wp-includes/load.php(278): wp_load_translations_early() #3 /data/web/virtuals/266053/virtual/www/domains/pernikovka.com/wp-settings.php(74): wp_maintenance() #4 /data/web/virtuals/266053/virtual/www/domains/pernikovka.com/wp-config.php(106): require_once(‚/data/web/virtu…‘) #5 /data/web/virtuals/266053/virtual/www/domains/pernikovka.com/wp-load.php(50): require_once(‚/data/web/virtu…‘) #6 /data/web/virtuals/266053/virtual/www/domains/pernikovka.com/wp-bl in /data/web/virtuals/266053/virtual/www/domains/pernikovka.com/wp-includes/class-wp-textdomain-registry.php on line 103