Fatal error: Uncaught Error: Call to undefined function mb_strtoupper() in /var/www/vhosts/fcsteaua.ro/wp-content/plugins/wordpress-seo/src/generators/schema/article.php:226
Stack trace:
#0 /var/www/vhosts/fcsteaua.ro/wp-content/plugins/wordpress-seo/src/generators/schema/article.php(60): Yoast\WP\SEO\Generators\Schema\Article->word_count()
#1 /var/www/vhosts/fcsteaua.ro/wp-content/plugins/wordpress-seo/src/generators/schema-generator.php(128): Yoast\WP\SEO\Generators\Schema\Article->generate()
#2 /var/www/vhosts/fcsteaua.ro/wp-content/plugins/wordpress-seo/src/generators/schema-generator.php(75): Yoast\WP\SEO\Generators\Schema_Generator->generate_graph()
#3 /var/www/vhosts/fcsteaua.ro/wp-content/plugins/wordpress-seo/src/presentations/indexable-presentation.php(720): Yoast\WP\SEO\Generators\Schema_Generator->generate()
#4 /var/www/vhosts/fcsteaua.ro/wp-content/plugins/wordpress-seo/src/presentations/abstract-presentation.php(66): Yoast\WP\SEO\Presentations\Indexable_Presentation->generate_schema()
#5 /var/www/vhosts/fcsteaua.ro/wp-content/plugins/wordpress-seo/src/presenters/schema-presenter.php(61): Yoast\WP\SEO\Presentations\Abstract_Presentation->__get()
#6 /var/www/vhosts/fcsteaua.ro/wp-content/plugins/wordpress-seo/src/presenters/schema-presenter.php(45): Yoast\WP\SEO\Presenters\Schema_Presenter->get()
#7 /var/www/vhosts/fcsteaua.ro/wp-content/plugins/wordpress-seo/src/integrations/front-end-integration.php(395): Yoast\WP\SEO\Presenters\Schema_Presenter->present()
#8 /var/www/vhosts/fcsteaua.ro/wp-includes/class-wp-hook.php(324): Yoast\WP\SEO\Integrations\Front_End_Integration->present_head()
#9 /var/www/vhosts/fcsteaua.ro/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters()
#10 /var/www/vhosts/fcsteaua.ro/wp-includes/plugin.php(517): WP_Hook->do_action()
#11 /var/www/vhosts/fcsteaua.ro/wp-content/plugins/wordpress-seo/src/integrations/front-end-integration.php(366): do_action()
#12 /var/www/vhosts/fcsteaua.ro/wp-includes/class-wp-hook.php(324): Yoast\WP\SEO\Integrations\Front_End_Integration->call_wpseo_head()
#13 /var/www/vhosts/fcsteaua.ro/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters()
#14 /var/www/vhosts/fcsteaua.ro/wp-includes/plugin.php(517): WP_Hook->do_action()
#15 /var/www/vhosts/fcsteaua.ro/wp-includes/general-template.php(3064): do_action()
#16 /var/www/vhosts/fcsteaua.ro/wp-content/themes/iconic-one/header.php(31): wp_head()
#17 /var/www/vhosts/fcsteaua.ro/wp-includes/template.php(810): require_once('...')
#18 /var/www/vhosts/fcsteaua.ro/wp-includes/template.php(745): load_template()
#19 /var/www/vhosts/fcsteaua.ro/wp-includes/general-template.php(48): locate_template()
#20 /var/www/vhosts/fcsteaua.ro/wp-content/themes/iconic-one/single.php(10): get_header()
#21 /var/www/vhosts/fcsteaua.ro/wp-includes/template-loader.php(106): include('...')
#22 /var/www/vhosts/fcsteaua.ro/wp-blog-header.php(19): require_once('...')
#23 /var/www/vhosts/fcsteaua.ro/index.php(17): require('...')
#24 {main}
thrown in /var/www/vhosts/fcsteaua.ro/wp-content/plugins/wordpress-seo/src/generators/schema/article.php on line 226