Class Magento\Elasticsearch\Model\Adapter\FieldMapper\ProductFieldMapper does not exist

[pramod kumar_th]

Upgraded Magento 2.3.1 to 2.4.1 recently. Everything seems fine with the website. When trying to login to Magento admin, below is what is displayed in the browser. Not sure what this means. Please advise as where to look for for a fix. Thanks

1 exception(s):
Exception #0 (ReflectionException): Class Magento\Elasticsearch\Model\Adapter\FieldMapper\ProductFieldMapper does not exist

Exception #0 (ReflectionException): Class Magento\Elasticsearch\Model\Adapter\FieldMapper\ProductFieldMapper does not exist
<pre>#1 Magento\Framework\Code\Reader\ClassReader->getConstructor() called at [vendor/magento/framework/ObjectManager/Definition/Runtime.php:54]
#2 Magento\Framework\ObjectManager\Definition\Runtime->getParameters() called at [vendor/magento/framework/ObjectManager/Factory/Compiled.php:100]
#3 Magento\Framework\ObjectManager\Factory\Compiled->create() called at [vendor/magento/framework/ObjectManager/ObjectManager.php:70]
#4 Magento\Framework\ObjectManager\ObjectManager->get() called at [vendor/wyomind/framework/Helper/License.php:11]
#5 Wyomind\Framework\Helper\License->constructor() called at [vendor/wyomind/elasticsearchbrowser/Helper/Data.php:28]
#6 Wyomind\ElasticsearchBrowser\Helper\Data->__construct() called at [vendor/magento/framework/ObjectManager/Factory/AbstractFactory.php:121]
#7 Magento\Framework\ObjectManager\Factory\AbstractFactory->createObject() called at [vendor/magento/framework/ObjectManager/Factory/Compiled.php:108]
#8 Magento\Framework\ObjectManager\Factory\Compiled->create() called at [vendor/magento/framework/ObjectManager/ObjectManager.php:70]
#9 Magento\Framework\ObjectManager\ObjectManager->get() called at [vendor/wyomind/framework/Helper/License.php:11]
#10 Wyomind\Framework\Helper\License->constructor() called at [vendor/wyomind/elasticsearchbrowser/Plugin/Ui/Config/Data.php:13]
#11 Wyomind\ElasticsearchBrowser\Plugin\Ui\Config\Data->__construct() called at [vendor/magento/framework/ObjectManager/Factory/AbstractFactory.php:121]
#12 Magento\Framework\ObjectManager\Factory\AbstractFactory->createObject() called at [vendor/magento/framework/ObjectManager/Factory/Compiled.php:108]
#13 Magento\Framework\ObjectManager\Factory\Compiled->create() called at [vendor/magento/framework/ObjectManager/ObjectManager.php:70]
#14 Magento\Framework\ObjectManager\ObjectManager->get() called at [vendor/magento/framework/Interception/PluginList/PluginList.php:174]
#15 Magento\Framework\Interception\PluginList\PluginList->getPlugin() called at [vendor/magento/framework/Interception/Interceptor.php:133]
#16 Magento\Ui\Config\Data\Interceptor->Magento\Framework\Interception\{closure}() called at [vendor/magento/framework/Interception/Interceptor.php:153]
#17 Magento\Ui\Config\Data\Interceptor->___callPlugins() called at [generated/code/Magento/Ui/Config/Data/Interceptor.php:23]
#18 Magento\Ui\Config\Data\Interceptor->get() called at [vendor/magento/framework/View/Layout/Reader/UiComponent.php:100]
#19 Magento\Framework\View\Layout\Reader\UiComponent->interpret() called at [vendor/magento/framework/View/Layout/ReaderPool.php:105]
#20 Magento\Framework\View\Layout\ReaderPool->interpret() called at [vendor/magento/framework/View/Layout/Reader/Container.php:84]
#21 Magento\Framework\View\Layout\Reader\Container->interpret() called at [vendor/magento/framework/View/Layout/ReaderPool.php:105]
#22 Magento\Framework\View\Layout\ReaderPool->interpret() called at [vendor/magento/framework/View/Page/Config/Reader/Body.php:68]
#23 Magento\Framework\View\Page\Config\Reader\Body->interpret() called at [vendor/magento/framework/View/Layout/ReaderPool.php:105]
#24 Magento\Framework\View\Layout\ReaderPool->interpret() called at [vendor/magento/framework/View/Layout.php:334]
#25 Magento\Framework\View\Layout->generateElements() called at [generated/code/Magento/Framework/View/Layout/Interceptor.php:32]
#26 Magento\Framework\View\Layout\Interceptor->generateElements() called at [vendor/magento/framework/View/Layout/Builder.php:129]
#27 Magento\Framework\View\Layout\Builder->generateLayoutBlocks() called at [vendor/magento/framework/View/Page/Builder.php:65]
#28 Magento\Framework\View\Page\Builder->generateLayoutBlocks() called at [vendor/magento/framework/View/Layout/Builder.php:65]
#29 Magento\Framework\View\Layout\Builder->build() called at [vendor/magento/framework/View/Page/Config.php:224]
#30 Magento\Framework\View\Page\Config->build() called at [vendor/magento/framework/View/Page/Config.php:237]
#31 Magento\Framework\View\Page\Config->publicBuild() called at [vendor/magento/framework/View/Result/Page.php:242]
#32 Magento\Framework\View\Result\Page->render() called at [vendor/magento/framework/View/Result/Layout.php:171]
#33 Magento\Framework\View\Result\Layout->renderResult() called at [generated/code/Magento/Backend/Model/View/Result/Page/Interceptor.php:23]
#34 Magento\Backend\Model\View\Result\Page\Interceptor->renderResult() called at [vendor/magento/framework/App/Http.php:120]
#35 Magento\Framework\App\Http->launch() called at [vendor/magento/framework/App/Bootstrap.php:263]
#36 Magento\Framework\App\Bootstrap->run() called at [index.php:39]
</pre>

[amitsamsukha]

the issue seems to be with some 3rd party extensions.

kindly check if you have Amasty Layered Navigation,

if yes kindly try to disable extension Amasty_Shopby

bin/magento module:disable Amasty_Shopby

bin/magento setup:di:compile

and run di:compile.

IF it helps you try to get an update from Amasty_Shopby for Magento2.4 

kindly Accept as a Solution if this works for you and give Kudos  

[pramod kumar_th]

List of enabled modules:
Magento_AdminAnalytics
Magento_Store
Magento_AdobeIms
Magento_AdobeImsApi
Magento_AdobeStockAdminUi
Magento_MediaGallery
Magento_AdobeStockAssetApi
Magento_AdobeStockClient
Magento_AdobeStockClientApi
Magento_AdobeStockImage
Magento_Directory
Magento_AdobeStockImageApi
Magento_AdvancedPricingImportExport
Magento_Theme
Magento_Amqp
Magento_AmqpStore
Magento_Config
Magento_Backend
Magento_Authorization
Magento_Search
Magento_Backup
Magento_Eav
Magento_Variable
Magento_BundleImportExport
Magento_CacheInvalidate
Magento_Customer
Magento_AdminNotification
Magento_Indexer
Magento_Security
Magento_GraphQl
Magento_EavGraphQl
Magento_Cms
Magento_CatalogImportExport
Magento_Catalog
Magento_CatalogInventory
Magento_Rule
Magento_Payment
Magento_CatalogRuleGraphQl
Magento_CatalogRule
Magento_CatalogUrlRewrite
Magento_StoreGraphQl
Magento_Widget
Magento_Quote
Magento_SalesSequence
Magento_CheckoutAgreementsGraphQl
Magento_MediaGalleryUi
Magento_CmsGraphQl
Magento_CmsUrlRewrite
Magento_CmsUrlRewriteGraphQl
Magento_ComposerRootUpdatePlugin
Magento_User
Magento_Msrp
Magento_Sales
Magento_CatalogGraphQl
Magento_Checkout
Magento_Contact
Magento_Cookie
Magento_Cron
Magento_Csp
Magento_CurrencySymbol
Magento_CatalogCustomerGraphQl
Magento_Integration
Magento_Downloadable
Magento_CustomerGraphQl
Magento_CustomerImportExport
Magento_Deploy
Magento_Developer
Magento_Dhl
Magento_Captcha
Magento_DirectoryGraphQl
Magento_QuoteGraphQl
Magento_DownloadableGraphQl
Magento_ImportExport
Magento_ConfigurableProduct
Magento_BundleGraphQl
Magento_CatalogSearch
Magento_AdvancedSearch
Magento_Elasticsearch
Magento_Email
Magento_EncryptionKey
Magento_Fedex
Magento_GiftMessage
Magento_GiftMessageGraphQl
Magento_GoogleAdwords
Magento_GoogleAnalytics
Magento_Ui
Magento_GoogleShoppingAds
Magento_CatalogCmsGraphQl
Magento_PageCache
Magento_GroupedProduct
Magento_GroupedImportExport
Magento_GroupedCatalogInventory
Magento_GroupedProductGraphQl
Magento_DownloadableImportExport
Magento_Bundle
Magento_InstantPurchase
Magento_Analytics
Magento_Inventory
Magento_InventoryAdminUi
Magento_InventoryAdvancedCheckout
Magento_InventoryApi
Magento_InventoryBundleImportExport
Magento_InventoryBundleProduct
Magento_InventoryBundleProductAdminUi
Magento_InventoryBundleProductIndexer
Magento_InventoryCatalog
Magento_InventorySales
Magento_InventoryCatalogAdminUi
Magento_InventoryCatalogApi
Magento_InventoryCatalogSearch
Magento_InventoryConfigurableProduct
Magento_InventoryConfigurableProductAdminUi
Magento_InventoryConfigurableProductIndexer
Magento_InventoryConfiguration
Magento_InventoryConfigurationApi
Magento_InventoryDistanceBasedSourceSelection
Magento_InventoryDistanceBasedSourceSelectionAdminUi
Magento_InventoryDistanceBasedSourceSelectionApi
Magento_InventoryElasticsearch
Magento_InventoryExportStockApi
Magento_InventoryIndexer
Magento_InventorySalesApi
Magento_InventoryGroupedProduct
Magento_InventoryGroupedProductAdminUi
Magento_InventoryGroupedProductIndexer
Magento_InventoryImportExport
Magento_InventoryInStorePickupApi
Magento_InventoryInStorePickupAdminUi
Magento_InventorySourceSelectionApi
Magento_InventoryInStorePickup
Magento_InventoryInStorePickupGraphQl
Magento_Shipping
Magento_InventoryInStorePickupShippingApi
Magento_InventoryInStorePickupQuoteGraphQl
Magento_InventoryInStorePickupSales
Magento_InventoryInStorePickupSalesApi
Magento_InventoryInStorePickupQuote
Magento_InventoryInStorePickupShipping
Magento_InventoryInStorePickupShippingAdminUi
Magento_Multishipping
Magento_Webapi
Magento_InventoryCache
Magento_InventoryLowQuantityNotification
Magento_Reports
Magento_InventoryLowQuantityNotificationApi
Magento_InventoryMultiDimensionalIndexerApi
Magento_InventoryProductAlert
Magento_InventoryRequisitionList
Magento_InventoryReservations
Magento_InventoryReservationCli
Magento_InventoryReservationsApi
Magento_InventoryExportStock
Magento_InventorySalesAdminUi
Magento_CatalogInventoryGraphQl
Magento_InventorySalesFrontendUi
Magento_InventorySetupFixtureGenerator
Magento_InventoryShipping
Magento_InventoryShippingAdminUi
Magento_InventorySourceDeductionApi
Magento_InventorySourceSelection
Magento_InventoryInStorePickupFrontend
Magento_InventoryVisualMerchandiser
Magento_LayeredNavigation
Magento_LoginAsCustomer
Magento_LoginAsCustomerAdminUi
Magento_LoginAsCustomerApi
Magento_LoginAsCustomerAssistance
Magento_LoginAsCustomerFrontendUi
Magento_LoginAsCustomerLog
Magento_LoginAsCustomerPageCache
Magento_LoginAsCustomerQuote
Magento_LoginAsCustomerSales
Magento_Marketplace
Magento_MediaContent
Magento_MediaContentApi
Magento_MediaContentCatalog
Magento_MediaContentCms
Magento_MediaContentSynchronization
Magento_MediaContentSynchronizationApi
Magento_MediaContentSynchronizationCatalog
Magento_MediaContentSynchronizationCms
Magento_AdobeStockAsset
Magento_MediaGalleryApi
Magento_MediaGalleryCatalog
Magento_MediaGalleryCatalogIntegration
Magento_MediaGalleryCatalogUi
Magento_MediaGalleryCmsUi
Magento_MediaGalleryIntegration
Magento_MediaGalleryMetadata
Magento_MediaGalleryMetadataApi
Magento_MediaGallerySynchronization
Magento_MediaGallerySynchronizationApi
Magento_MediaGallerySynchronizationMetadata
Magento_AdobeStockImageAdminUi
Magento_MediaGalleryUiApi
Magento_MediaStorage
Magento_MessageQueue
Magento_CatalogRuleConfigurable
Magento_MsrpConfigurableProduct
Magento_MsrpGroupedProduct
Magento_InventoryInStorePickupMultishipping
Magento_MysqlMq
Magento_NewRelicReporting
Magento_Newsletter
Magento_NewsletterGraphQl
Magento_OfflinePayments
Magento_SalesRule
Magento_GraphQlCache
Magento_CardinalCommerce
Magento_Vault
Magento_Paypal
Magento_PaypalGraphQl
Magento_Persistent
Magento_ProductAlert
Magento_ProductVideo
Magento_CheckoutAgreements
Magento_QuoteAnalytics
Magento_QuoteBundleOptions
Magento_QuoteConfigurableOptions
Magento_QuoteDownloadableLinks
Magento_ConfigurableProductGraphQl
Magento_ReCaptchaAdminUi
Magento_ReCaptchaCheckout
Magento_ReCaptchaContact
Magento_ReCaptchaCustomer
Magento_ReCaptchaFrontendUi
Magento_ReCaptchaMigration
Magento_ReCaptchaNewsletter
Magento_ReCaptchaPaypal
Magento_ReCaptchaReview
Magento_ReCaptchaSendFriend
Magento_ReCaptchaUi
Magento_ReCaptchaUser
Magento_ReCaptchaValidation
Magento_ReCaptchaValidationApi
Magento_ReCaptchaVersion2Checkbox
Magento_ReCaptchaVersion2Invisible
Magento_ReCaptchaVersion3Invisible
Magento_RelatedProductGraphQl
Magento_ReleaseNotification
Magento_InventoryLowQuantityNotificationAdminUi
Magento_RequireJs
Magento_Review
Magento_ReviewAnalytics
Magento_ReviewGraphQl
Magento_Robots
Magento_Rss
Magento_ConfigurableProductSales
Magento_SalesAnalytics
Magento_SalesGraphQl
Magento_SalesInventory
Magento_OfflineShipping
Magento_ConfigurableImportExport
Magento_UrlRewrite
Magento_Elasticsearch7
Magento_CustomerAnalytics
Magento_Securitytxt
Magento_SendFriend
Magento_SendFriendGraphQl
Magento_InventoryInStorePickupSalesAdminUi
Magento_Sitemap
Magento_UrlRewriteGraphQl
Magento_CustomerDownloadableGraphQl
Magento_Swagger
Magento_SwaggerWebapi
Magento_SwaggerWebapiAsync
Magento_Swatches
Magento_SwatchesGraphQl
Magento_SwatchesLayeredNavigation
Magento_Tax
Magento_TaxGraphQl
Magento_TaxImportExport
Magento_AsynchronousOperations
Magento_ThemeGraphQl
Magento_Tinymce3
Magento_Translation
Magento_TwoFactorAuth
Magento_GoogleOptimizer
Magento_Ups
Magento_SampleData
Magento_CatalogUrlRewriteGraphQl
Magento_CatalogAnalytics
Magento_Usps
Magento_InventoryGraphQl
Magento_PaypalCaptcha
Magento_VaultGraphQl
Magento_Version
Magento_InventoryInStorePickupWebapiExtension
Magento_WebapiAsync
Magento_WebapiSecurity
Magento_Weee
Magento_WeeeGraphQl
Magento_CatalogWidget
Magento_Wishlist
Magento_WishlistAnalytics
Magento_WishlistGraphQl
Amazon_Core
Amazon_Login
Amazon_Payment
CloudFlare_Plugin
Dotdigitalgroup_Email
Dotdigitalgroup_Chat
Klarna_Core
Klarna_Ordermanagement
Klarna_Kp
Klarna_Onsitemessaging
Klarna_KpGraphQl
Mageplaza_Core
Mageplaza_ImageOptimizer
PayPal_Braintree
PayPal_BraintreeGraphQl
Perfectmakeupmirrors_CustomShipping
Perfectmakeupmirrors_LogoHeader
Perfectmakeupmirrors_Order
Perfectmakeupmirrors_PmmLayout
StripeIntegration_Payments
Swissup_Ajaxpro
Swissup_Core
Swissup_Amp
Swissup_Askit
Swissup_Attributepages
Swissup_Codemirror
Swissup_Compare
Swissup_Ajaxsearch
Swissup_EasySlide
Swissup_Easybanner
Swissup_Easycatalogimg
Swissup_Easytabs
Swissup_Fblike
Swissup_FeaturedAttributes
Swissup_FontAwesome
Swissup_Gdpr
Swissup_GdprAskit
Swissup_GdprTestimonials
Swissup_Highlight
Swissup_HoverGallery
Swissup_Hreflang
Swissup_Image
Swissup_Lightboxpro
Swissup_Marketplace
Swissup_Navigationpro
Swissup_Pagespeed
Swissup_ProLabels
Swissup_QuantitySwitcher
Swissup_Reviewreminder
Swissup_RichSnippets
Swissup_Rtl
Swissup_SeoCanonical
Swissup_SeoCore
Swissup_SeoCrossLinks
Swissup_SeoHtmlSitemap
Swissup_SeoImages
Swissup_SeoPager
Swissup_SeoTemplates
Swissup_SeoUrls
Swissup_SeoXmlSitemap
Swissup_SlickCarousel
Swissup_SoldTogether
Swissup_Stickyfill
Swissup_Suggestpage
Swissup_Testimonials
Swissup_ThemeEditor
Swissup_ThemeEditorArgentoEssence
Swissup_ThemeEditorArgentoFlat
Swissup_ThemeEditorArgentoForce
Swissup_ThemeEditorArgentoLuxury
Swissup_ThemeEditorArgentoMall
Swissup_ThemeEditorArgentoPure2
Swissup_ThemeEditorArgentoStripes
Temando_ShippingRemover
Vertex_AddressValidationApi
Vertex_AddressValidation
Wyomind_Core
Wyomind_Framework
Wyomind_DataFeedManager
Wyomind_ElasticsearchBrowser
Wyomind_CronScheduler
Wyomind_Watchlog
Yotpo_Yotpo

List of disabled modules:
Magento_Elasticsearch6
Vertex_Tax

[amitsamsukha]

@pramod kumar_th ,

you need to check this by disabling the extensions 

you can do that in groups like disable all extensions from VendorA and check.