He actualizado el sitio web de 2.1.6 a 2.2.1 y no puedo serializar el error de valor en el front-end y el back-end.
{"0":"Unable to serialize value.","1":"#0 \/var\/www\/vhosts\/demo.com\/eiselec\/vendor\/magento\/framework\/Translate.php(494): Magento\\Framework\\Serialize\\Serializer\\Json->serialize(Array)\n
#1 \/var\/www\/vhosts\/demo.com\/eiselec\/vendor\/magento\/framework\/Translate.php(190): Magento\\Framework\\Translate->_saveCache()\n
#2 \/var\/www\/vhosts\/demo.com\/eiselec\/vendor\/magento\/framework\/App\/Area.php(244): Magento\\Framework\\Translate->loadData(NULL, false)\n
#3 \/var\/www\/vhosts\/demo.com\/eiselec\/vendor\/magento\/framework\/App\/Area.php(215): Magento\\Framework\\App\\Area->_initTranslate()\n
#4 \/var\/www\/vhosts\/demo.com\/eiselec\/vendor\/magento\/framework\/App\/Area.php(142): Magento\\Framework\\App\\Area->_loadPart('translate')\n
#5 \/var\/www\/vhosts\/demo.com\/eiselec\/vendor\/magento\/framework\/View\/DesignLoader.php(55): Magento\\Framework\\App\\Area->load('translate')\n
#6 \/var\/www\/vhosts\/demo.com\/eiselec\/vendor\/magento\/framework\/App\/Action\/Plugin\/Design.php(48): Magento\\Framework\\View\\DesignLoader->load()\n
#7 \/var\/www\/vhosts\/demo.com\/eiselec\/vendor\/magento\/framework\/Interception\/Interceptor.php(121): Magento\\Framework\\App\\Action\\Plugin\\Design->beforeDispatch(Object(Magento\\Cms\\Controller\\Index\\Index\\Interceptor), Object(Magento\\Framework\\App\\Request\\Http))\n
#8 \/var\/www\/vhosts\/demo.com\/eiselec\/vendor\/magento\/framework\/Interception\/Interceptor.php(153): Magento\\Cms\\Controller\\Index\\Index\\Interceptor->Magento\\Framework\\Interception\\{closure}(Object(Magento\\Framework\\App\\Request\\Http))\n
#9 \/var\/www\/vhosts\/demo.com\/eiselec\/generated\/code\/Magento\/Cms\/Controller\/Index\/Index\/Interceptor.php(39): Magento\\Cms\\Controller\\Index\\Index\\Interceptor->___callPlugins('dispatch', Array, Array)\n
#10 \/var\/www\/vhosts\/demo.com\/eiselec\/vendor\/magento\/framework\/App\/FrontController.php(55): Magento\\Cms\\Controller\\Index\\Index\\Interceptor->dispatch(Object(Magento\\Framework\\App\\Request\\Http))\n
#11 \/var\/www\/vhosts\/demo.com\/eiselec\/vendor\/magento\/framework\/Interception\/Interceptor.php(58): Magento\\Framework\\App\\FrontController->dispatch(Object(Magento\\Framework\\App\\Request\\Http))\n
#12 \/var\/www\/vhosts\/demo.com\/eiselec\/vendor\/magento\/framework\/Interception\/Interceptor.php(138): Magento\\Framework\\App\\FrontController\\Interceptor->___callParent('dispatch', Array)\n
#13 \/var\/www\/vhosts\/demo.com\/eiselec\/vendor\/magento\/module-store\/App\/FrontController\/Plugin\/RequestPreprocessor.php(94): Magento\\Framework\\App\\FrontController\\Interceptor->Magento\\Framework\\Interception\\{closure}(Object(Magento\\Framework\\App\\Request\\Http))\n
#14 \/var\/www\/vhosts\/demo.com\/eiselec\/vendor\/magento\/framework\/Interception\/Interceptor.php(135): Magento\\Store\\App\\FrontController\\Plugin\\RequestPreprocessor->aroundDispatch(Object(Magento\\Framework\\App\\FrontController\\Interceptor), Object(Closure), Object(Magento\\Framework\\App\\Request\\Http))\n
#15 \/var\/www\/vhosts\/demo.com\/eiselec\/vendor\/magento\/module-page-cache\/Model\/App\/FrontController\/BuiltinPlugin.php(73): Magento\\Framework\\App\\FrontController\\Interceptor->Magento\\Framework\\Interception\\{closure}(Object(Magento\\Framework\\App\\Request\\Http))\n
#16 \/var\/www\/vhosts\/demo.com\/eiselec\/vendor\/magento\/framework\/Interception\/Interceptor.php(135): Magento\\PageCache\\Model\\App\\FrontController\\BuiltinPlugin->aroundDispatch(Object(Magento\\Framework\\App\\FrontController\\Interceptor), Object(Closure), Object(Magento\\Framework\\App\\Request\\Http))\n
#17 \/var\/www\/vhosts\/demo.com\/eiselec\/vendor\/magento\/framework\/Interception\/Interceptor.php(153): Magento\\Framework\\App\\FrontController\\Interceptor->Magento\\Framework\\Interception\\{closure}(Object(Magento\\Framework\\App\\Request\\Http))\n
#18 \/var\/www\/vhosts\/demo.com\/eiselec\/generated\/code\/Magento\/Framework\/App\/FrontController\/Interceptor.php(26): Magento\\Framework\\App\\FrontController\\Interceptor->___callPlugins('dispatch', Array, NULL)\n
#19 \/var\/www\/vhosts\/demo.com\/eiselec\/vendor\/magento\/framework\/App\/Http.php(135): Magento\\Framework\\App\\FrontController\\Interceptor->dispatch(Object(Magento\\Framework\\App\\Request\\Http))\n
#20 \/var\/www\/vhosts\/demo.com\/eiselec\/vendor\/magento\/framework\/App\/Bootstrap.php(256): Magento\\Framework\\App\\Http->launch()\n
#21 \/var\/www\/vhosts\/demo.com\/eiselec\/index.php(39): Magento\\Framework\\App\\Bootstrap->run(Object(Magento\\Framework\\App\\Http))\n
#22 {main}","url":"\/","script_name":"\/index.php"}
Déjame saber cómo puedo resolverlo.
Gracias