Fatal error: Uncaught Error: Call to undefined function FluentForm\Framework\Support\mb_strtoupper() in /home3/letterbox/public_html/wp-content/plugins/fluentform/vendor/wpfluent/framework/src/WPFluent/Support/Str.php:1318
Stack trace:
#0 /home3/letterbox/public_html/wp-content/plugins/fluentform/vendor/wpfluent/framework/src/WPFluent/Support/Str.php(1720): FluentForm\Framework\Support\Str::upper()
#1 /home3/letterbox/public_html/wp-content/plugins/fluentform/vendor/wpfluent/framework/src/WPFluent/Support/Str.php(1580): FluentForm\Framework\Support\Str::ucfirst()
#2 [internal function]: FluentForm\Framework\Support\Str::{closure:FluentForm\Framework\Support\Str::studly():1579}()
#3 /home3/letterbox/public_html/wp-content/plugins/fluentform/vendor/wpfluent/framework/src/WPFluent/Support/Str.php(1579): array_map()
#4 /home3/letterbox/public_html/wp-content/plugins/fluentform/vendor/wpfluent/framework/src/WPFluent/Database/Orm/Concerns/HasAttributes.php(613): FluentForm\Framework\Support\Str::studly()
#5 /home3/letterbox/public_html/wp-content/plugins/fluentform/vendor/wpfluent/framework/src/WPFluent/Database/Orm/Concerns/HasAttributes.php(2024): FluentForm\Framework\Database\Orm\Model->hasGetMutator()
#6 /home3/letterbox/public_html/wp-content/plugins/fluentform/vendor/wpfluent/framework/src/WPFluent/Database/Orm/Concerns/HasAttributes.php(500): FluentForm\Framework\Database\Orm\Model->transformModelValue()
#7 /home3/letterbox/public_html/wp-content/plugins/fluentform/vendor/wpfluent/framework/src/WPFluent/Database/Orm/Concerns/HasAttributes.php(453): FluentForm\Framework\Database\Orm\Model->getAttributeValue()
#8 /home3/letterbox/public_html/wp-content/plugins/fluentform/vendor/wpfluent/framework/src/WPFluent/Database/Orm/Model.php(1989): FluentForm\Framework\Database\Orm\Model->getAttribute()
#9 /home3/letterbox/public_html/wp-content/plugins/fluentform/app/Helpers/Helper.php(184): FluentForm\Framework\Database\Orm\Model->__get()
#10 /home3/letterbox/public_html/wp-content/plugins/fluentform/app/Modules/Component/Component.php(537): FluentForm\App\Helpers\Helper::getFormMeta()
#11 /home3/letterbox/public_html/wp-content/plugins/fluentform/app/Modules/Component/Component.php(484): FluentForm\App\Modules\Component\Component->renderForm()
#12 /home3/letterbox/public_html/wp-includes/shortcodes.php(434): FluentForm\App\Modules\Component\Component->{closure:FluentForm\App\Modules\Component\Component::addFluentFormShortCode():467}()
#13 [internal function]: do_shortcode_tag()
#14 /home3/letterbox/public_html/wp-includes/shortcodes.php(273): preg_replace_callback()
#15 /home3/letterbox/public_html/wp-content/plugins/elementor/includes/widgets/shortcode.php(141): do_shortcode()
#16 /home3/letterbox/public_html/wp-content/plugins/elementor/includes/base/controls-stack.php(2374): Elementor\Widget_Shortcode->render()
#17 /home3/letterbox/public_html/wp-content/plugins/elementor/includes/base/widget-base.php(636): Elementor\Controls_Stack->render_by_mode()
#18 /home3/letterbox/public_html/wp-content/plugins/elementor/includes/base/widget-base.php(774): Elementor\Widget_Base->render_content()
#19 /home3/letterbox/public_html/wp-content/plugins/elementor/includes/base/element-base.php(494): Elementor\Widget_Base->print_content()
#20 /home3/letterbox/public_html/wp-content/plugins/elementor/modules/element-cache/module.php(71): Elementor\Element_Base->print_element()
#21 /home3/letterbox/public_html/wp-includes/shortcodes.php(434): Elementor\Modules\ElementCache\Module->{closure:Elementor\Modules\ElementCache\Module::register_shortcode():51}()
#22 [internal function]: do_shortcode_tag()
#23 /home3/letterbox/public_html/wp-includes/shortcodes.php(273): preg_replace_callback()
#24 /home3/letterbox/public_html/wp-content/plugins/elementor/core/base/document.php(1888): do_shortcode()
#25 /home3/letterbox/public_html/wp-content/plugins/elementor/core/base/document.php(1221): Elementor\Core\Base\Document->print_elements()
#26 /home3/letterbox/public_html/wp-content/plugins/elementor/includes/frontend.php(1210): Elementor\Core\Base\Document->print_elements_with_wrapper()
#27 /home3/letterbox/public_html/wp-content/plugins/elementor/includes/frontend.php(1105): Elementor\Frontend->get_builder_content()
#28 /home3/letterbox/public_html/wp-includes/class-wp-hook.php(341): Elementor\Frontend->apply_builder_in_content()
#29 /home3/letterbox/public_html/wp-includes/plugin.php(205): WP_Hook->apply_filters()
#30 /home3/letterbox/public_html/wp-includes/post-template.php(256): apply_filters()
#31 /home3/letterbox/public_html/wp-content/plugins/elementor/modules/page-templates/module.php(188): the_content()
#32 [internal function]: Elementor\Modules\PageTemplates\Module->print_callback()
#33 /home3/letterbox/public_html/wp-content/plugins/elementor/modules/page-templates/module.php(205): call_user_func()
#34 /home3/letterbox/public_html/wp-content/plugins/elementor/modules/page-templates/templates/header-footer.php(19): Elementor\Modules\PageTemplates\Module->print_content()
#35 /home3/letterbox/public_html/wp-includes/template-loader.php(132): include('/home3/letterbo...')
#36 /home3/letterbox/public_html/wp-blog-header.php(19): require_once('/home3/letterbo...')
#37 /home3/letterbox/public_html/index.php(17): require('/home3/letterbo...')
#38 {main}
thrown in /home3/letterbox/public_html/wp-content/plugins/fluentform/vendor/wpfluent/framework/src/WPFluent/Support/Str.php on line 1318
