Fatal error: Cannot redeclare wp_add_editor_classic_theme_styles() (previously declared in /home/.sites/86/site581/web/wp-includes/deprecated.php:6438) in /home/.sites/86/site581/web/wp-includes/script-loader.php on line 3326

Fatal error: Uncaught Error: Call to a member function set() on null in /home/.sites/86/site581/web/wp-includes/l10n.php:857
Stack trace:
#0 /home/.sites/86/site581/web/wp-includes/l10n.php(960): load_textdomain('default', '/home/.sites/86...', 'de_DE')
#1 /home/.sites/86/site581/web/wp-includes/class-wp-fatal-error-handler.php(49): load_default_textdomain()
#2 [internal function]: WP_Fatal_Error_Handler->handle()
#3 {main}
  thrown in /home/.sites/86/site581/web/wp-includes/l10n.php on line 857