FATAL ERROR

Hi, how are you?

Can you help me with thir error below?

My current version of php is 7.1 also the version 7.3 have the same error.

Thank you so much

PHP Fatal error: Uncaught Error: Call to undefined function WPBannerize\WPBones\Support\mb_strtolower() in /home/diariomscom/public_html/wp-content/plugins/wp-bannerize-pro/vendor/wpbones/wpbones/src/Support/Str.php:351
Stack trace:
#0 /home/diariomscom/public_html/wp-content/plugins/wp-bannerize-pro/vendor/wpbones/wpbones/src/Foundation/Plugin.php(356): WPBannerize\WPBones\Support\Str::slug(‘wp-bannerize-ad…’)
#1 /home/diariomscom/public_html/wp-content/plugins/wp-bannerize-pro/plugin/Providers/WPBannerizeServiceProvider.php(33): WPBannerize\WPBones\Foundation\Plugin->css(‘wp-bannerize-ad…’)
#2 /home/diariomscom/public_html/wp-content/plugins/wp-bannerize-pro/vendor/wpbones/wpbones/src/Foundation/Plugin.php(499): WPBannerize\Providers\WPBannerizeServiceProvider->register()
#3 /home/diariomscom/public_html/wp-includes/class-wp-hook.php(286): WPBannerize\WPBones\Foundation\Plugin->init(”)
#4 /home/diariomscom/public_html/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(NULL, Array)
#5 /home/diariomscom/public_ht in /home/diariomscom/public_html/wp-content/plugins/wp-bannerize-pro/vendor/wpbones/wpbones/src/Support/Str.php on line 351

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