[Resolved] Fatal error: Uncaught Error: Call to undefined function

I have below error everytime I tried to translate a page or products, I tried to remove the sitepress-multilingual-cms plugin and then download sitepress-multilingual-cms.4.6.4.zip from your website, install and activate again, but no luck , still got this error, please help.
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Fatal error: Uncaught Error: Call to undefined function mb_ereg_replace_callback() in /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/classes/xliff/class-wpml-tm-validate-html.php:124 Stack trace: #0 /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/classes/xliff/class-wpml-tm-validate-html.php(34): WPML_TM_Validate_HTML->hide_wp_bugs() #1 /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/classes/xliff/wpml-tm-xliff.php(196): WPML_TM_Validate_HTML->validate() #2 /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/classes/xliff/wpml-tm-xliff.php(169): WPML_TM_XLIFF->validate() #3 /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/classes/xliff/wpml-tm-xliff.php(141): WPML_TM_XLIFF->appendData() #4 /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/classes/xliff/class-wpml-tm-xliff-writer.php(133): WPML_TM_XLIFF->setTranslationUnits() #5 /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/classes/xliff/class-wpml-tm-xliff-writer.php(69): WPML_TM_Xliff_Writer->generate_xliff() #6 /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/inc/functions-load-tm.php(568): WPML_TM_Xliff_Writer->generate_job_xliff() #7 /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/inc/functions-load-tm.php(541): wpml_tm_get_job_xliff() #8 /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/classes/ATE/Hooks/class-wpml-tm-ate-jobs-actions.php(153): wpml_tm_create_ATE_job_creation_model() #9 [internal function]: WPML_TM_ATE_Jobs_Actions->{closure}() #10 /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/vendor/wpml/fp/core/Fns.php(164): array_map() #11 [internal function]: WPML\FP\Fns::WPML\FP\{closure}() #12 /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/vendor/wpml/fp/core/functions.php(154): call_user_func_array() #13 [internal function]: WPML\FP\Fns::WPML\FP\{closure}() #14 /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/vendor/wpml/collect/src/Illuminate/Support/Traits/Macroable.php(56): call_user_func_array() #15 /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/classes/ATE/Hooks/class-wpml-tm-ate-jobs-actions.php(152): WPML\FP\Fns::__callStatic() #16 /home/hkdetcom/v3.hk-delight.com/wp-includes/class-wp-hook.php(308): WPML_TM_ATE_Jobs_Actions->added_translation_jobs() #17 /home/hkdetcom/v3.hk-delight.com/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters() #18 /home/hkdetcom/v3.hk-delight.com/wp-includes/plugin.php(517): WP_Hook->do_action() #19 /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/inc/translation-management/translation-management.class.php(1469): do_action() #20 /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/classes/class-wpml-translation-job-factory.php(112): TranslationManagement->send_jobs() #21 /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/classes/jobs/Manual.php(121): WPML_Translation_Job_Factory->create_local_job() #22 /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/classes/jobs/Manual.php(39): WPML\TM\Jobs\Manual->createLocalJob() #23 /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/vendor/wpml/fp/core/Either.php(207): WPML\TM\Jobs\Manual->createOrReuse() #24 /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/classes/editor/Editor.php(85): WPML\FP\Right->map() #25 /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/classes/menu/translation-queue/class-wpml-translations-queue.php(52): WPML\TM\Editor\Editor->open() #26 /home/hkdetcom/v3.hk-delight.com/wp-includes/class-wp-hook.php(308): WPML_Translations_Queue->load() #27 /home/hkdetcom/v3.hk-delight.com/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters() #28 /home/hkdetcom/v3.hk-delight.com/wp-includes/plugin.php(517): WP_Hook->do_action() #29 /home/hkdetcom/v3.hk-delight.com/wp-admin/includes/class-wp-screen.php(424): do_action() #30 /home/hkdetcom/v3.hk-delight.com/wp-admin/includes/screen.php(243): WP_Screen->set_current_screen() #31 /home/hkdetcom/v3.hk-delight.com/wp-admin/admin.php(212): set_current_screen() #32 {main} thrown in /home/hkdetcom/v3.hk-delight.com/wp-content/plugins/sitepress-multilingual-cms/classes/xliff/class-wpml-tm-validate-html.php on line 124
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