Arreglar errores Prestashop (Debug) y mejorar en rendimiento

Tengo prestashop 1.7.3 y me senyala Parámetros requeridos: Por favor, corrige el (los) siguiente(s) error(es). La página tarda mucho en cargar y en Safari da errores. (El servidor por el momento no es el mejor (1and1) pero es una cuenta que tenia de hace tiempo y quiero migrarlo)

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ContextErrorException in smarty_internal_templatebase.php(157) : eval()'d code line 59:
Notice: Undefined index: search_string
in smarty_internal_templatebase.php(157) : eval()'d code line 59
at ErrorHandler->handleError('8', 'Undefined index: search_string', '/homepages/43/d446664590/htdocs/vendor/prestashop/smarty/sysplugins/smarty_internal_templatebase.php(157) : eval()'d code', '59', array('_smarty_tpl' => object(Smartydevtemplate), '_from' => array(array('id_category' => '118', 'name' => ' alimentos eco'), array('id_category' => '124', 'name' => '-- aceites y condimentos'), array('id_category' => '125', 'name' => '-- aperitivos y olivas'), array('id_category' => '126', 'name' => '-- pasta, cereales y legumbres'), array('id_category' => '127', 'name' => '-- conservas, patés y salsas'), array('id_category' => '128', 'name' => '-- desayunos y meriendas'), array('id_category' => '129', 'name' => '-- cafés e infusiones'), array('id_category' => '130', 'name' => '-- pan ecológico'), array('id_category' => '131', 'name' => '-- azúcares, mieles y edulcorante'), array('id_category' => '132', 'name' => '-- chocolate, cacao y cremas'), array('id_category' => '133', 'name' => '-- bebidas ecológicas'), array('id_category' => '137', 'name' => '-- alimentación japonesa'), array('id_category' => '134', 'name' => '-- comida preparada'), array('id_category' => '135', 'name' => '-- sopas y cremas'), array('id_category' => '136', 'name' => '-- postres vegetales'), array('id_category' => '119', 'name' => ' complementos / parafarmacia'), array('id_category' => '138', 'name' => '-- complementos nutricionales'), array('id_category' => '139', 'name' => '-- nutrición deportiva'), array('id_category' => '140', 'name' => '-- superalimentos'), array('id_category' => '141', 'name' => '-- dieta consum'), array('id_category' => '142', 'name' => '-- flor de bach'), array('id_category' => '143', 'name' => '-- esencias'), array('id_category' => '144', 'name' => '-- parafarmacia'), array('id_category' => '120', 'name' => ' infantil'), array('id_category' => '145', 'name' => '-- alimentación infantil'), array('id_category' => '146', 'name' => '-- higiene infantil'), array('id_category' => '147', 'name' => '-- complementos nutricionales'), array('id_category' => '148', 'name' => '-- accesorios'), array('id_category' => '121', 'name' => ' cosmética / higiene'), array('id_category' => '149', 'name' => '-- cuidado corporal y facial'), array('id_category' => '150', 'name' => '-- cuidado facial'), array('id_category' => '151', 'name' => '-- cuidado capilar'), array('id_category' => '152', 'name' => '-- higiene bucal'), array('id_category' => '153', 'name' => '-- higiene corporal'), array('id_category' => '154', 'name' => '-- higiene femenina'), array('id_category' => '155', 'name' => '-- gama solar'), array('id_category' => '156', 'name' => '-- tintes y colorantes'), array('id_category' => '122', 'name' => ' limpieza eco'), array('id_category' => '157', 'name' => '-- limpieza hogar'), array('id_category' => '158', 'name' => '-- limpieza ropa'), array('id_category' => '159', 'name' => '-- lavavajillas ecológicas'), array('id_category' => '123', 'name' => ' más'), array('id_category' => '160', 'name' => '-- accesorios'), array('id_category' => '226', 'name' => ' agua de mar')))) in smarty_internal_templatebase.php(157) : eval()'d code line 59
at content_5b44c544eab7e6_91552071(object(SmartyDevTemplate)) in smarty_internal_templatebase.php line 188
at Smarty_Internal_TemplateBase->fetch(object(SmartyDevTemplate), null, null, null, false, true, false) in SmartyDevTemplate.php line 41
at SmartyDevTemplateCore->fetch() in Module.php line 2244
at ModuleCore->display('/homepages/43/d446664590/htdocs/modules/tvcmssearch/tvcmssearch.php', 'views/templates/front/tvcmssearch.tpl') in tvcmssearch.php line 80
at TvcmsSearch->hookdisplayNav3() in tvcmssearch.php line 97
at TvcmsSearch->hookdisplaySearch(array('smarty' => object(SmartyDevTemplate), 'cookie' => object(Cookie), 'cart' => object(Cart), 'altern' => '1')) in Hook.php line 924
at HookCore::coreCallHook(object(TvcmsSearch), 'hookdisplaySearch', array('smarty' => object(SmartyDevTemplate), 'cookie' => object(Cookie), 'cart' => object(Cart), 'altern' => '1')) in Hook.php line 328
at HookCore::callHookOn(object(TvcmsSearch), 'displaySearch', array('smarty' => object(SmartyDevTemplate), 'cookie' => object(Cookie), 'cart' => object(Cart), 'altern' => '1')) in Hook.php line 860
at HookCore::exec('displaySearch', array('smarty' => object(SmartyDevTemplate), 'cookie' => object(Cookie), 'cart' => object(Cart), 'altern' => '1'), null) in smarty.config.inc.php line 168
at smartyHook(array('h' => 'displaySearch'), object(SmartyDevTemplate)) in SmartyLazyRegister.php line 83
at SmartyLazyRegister->__call('smartyHook', array(array('h' => 'displaySearch'), object(SmartyDevTemplate))) in smarty_internal_templatebase.php(157) : eval()'d code line 833
at content_5b44c544e0c2a6_62143020(object(SmartyDevTemplate)) in smarty_internal_templatebase.php(157) : eval()'d code line 390
at content_5b44c544e58a33_88015723(object(SmartyDevTemplate)) in smarty_internal_templatebase.php line 188
at Smarty_Internal_TemplateBase->fetch('index.tpl', null, 'layouts/layout-left-column.tpl', object(SmartyDev), false, true, false) in SmartyDev.php line 41
at SmartyDev->fetch('index.tpl', null, 'layouts/layout-left-column.tpl') in FrontController.php line 669
at FrontControllerCore->smartyOutputContent('index.tpl') in FrontController.php line 653
at FrontControllerCore->display() in Controller.php line 225
at ControllerCore->run() in Dispatcher.php line 428
at DispatcherCore->dispatch() in index.p
hp line 28