diff --git a/mailpoet/lib/Doctrine/CacheOnlyMappingDriver.php b/mailpoet/lib/Doctrine/CacheOnlyMappingDriver.php
new file mode 100644
index 0000000000..3ef0ba7462
--- /dev/null
+++ b/mailpoet/lib/Doctrine/CacheOnlyMappingDriver.php
@@ -0,0 +1,55 @@
+<?php declare(strict_types=1);
+
+namespace MailPoet\Doctrine;
+
+use MailPoet\RuntimeException;
+use MailPoetVendor\Doctrine\Persistence\Mapping\ClassMetadata;
+use MailPoetVendor\Doctrine\Persistence\Mapping\Driver\MappingDriver;
+use MailPoetVendor\Psr\Cache\CacheItemPoolInterface;
+
+/**
+ * Intended to be used in production environment where we rely on metadata cache for reading all metadata.
+ */
+class CacheOnlyMappingDriver implements MappingDriver {
+  /** @var string */
+  protected $cacheSalt = '__CLASSMETADATA__';
+
+  /** @var CacheItemPoolInterface */
+  private $metaDataCache;
+
+  public function __construct(
+    CacheItemPoolInterface $metaDataCache
+  ) {
+    $this->metaDataCache = $metaDataCache;
+  }
+
+  /**
+   * @inerhitDoc
+   */
+  public function loadMetadataForClass($className, ClassMetadata $metadata) {
+    // We don't need to load anything it is all cached.
+  }
+
+  /**
+   * @inerhitDoc
+   */
+  public function getAllClassNames() {
+    throw new RuntimeException('CacheOnlyMappingDriver::getAllClassNames should not be called');
+  }
+
+  /**
+   * @inerhitDoc
+   */
+  public function isTransient($className) {
+    // Everything in cache are metadata and class with metadata is non-transient
+    // See https://github.com/doctrine/persistence/blob/b07e347a24e7a19a2b6462e00a6dff899e4c2dd2/src/Persistence/Mapping/Driver/MappingDriver.php#L34
+    return !$this->metaDataCache->hasItem($this->getCacheKey($className));
+  }
+
+  /**
+   * Copy pasted from MailPoetVendor\Doctrine\Persistence\Mapping\AbstractClassMetadataFactory
+   */
+  protected function getCacheKey(string $className) : string {
+    return str_replace('\\', '__', $className) . $this->cacheSalt;
+  }
+}
diff --git a/mailpoet/lib/Doctrine/ConfigurationFactory.php b/mailpoet/lib/Doctrine/ConfigurationFactory.php
index 18f6e8d16a..db8cd0982d 100644
--- a/mailpoet/lib/Doctrine/ConfigurationFactory.php
+++ b/mailpoet/lib/Doctrine/ConfigurationFactory.php
@@ -6,7 +6,6 @@ use MailPoet\Doctrine\Annotations\AnnotationReaderProvider;
 use MailPoetVendor\Doctrine\Common\Proxy\AbstractProxyFactory;
 use MailPoetVendor\Doctrine\ORM\Configuration;
 use MailPoetVendor\Doctrine\ORM\Mapping\Driver\AnnotationDriver;
-use MailPoetVendor\Doctrine\Persistence\Mapping\Driver\PHPDriver;
 use MailPoetVendor\Doctrine\ORM\Mapping\UnderscoreNamingStrategy;
 
 class ConfigurationFactory {
@@ -41,17 +40,15 @@ class ConfigurationFactory {
 
     // annotation reader exists only in dev environment, on production cache is pre-generated
     $annotationReader = $this->annotationReaderProvider->getAnnotationReader();
-    if ($annotationReader) {
-      $configuration->setMetadataDriverImpl(new AnnotationDriver($annotationReader, [self::ENTITY_DIR]));
-    } else {
-      // Should never be called but Doctrine requires having driver set
-      $configuration->setMetadataDriverImpl(new PHPDriver([]));
-    }
-
-    // metadata cache (for production cache is pre-generated at build time)
     $isReadOnly = !$annotationReader;
     $metadataStorage = new PSRMetadataCache(self::METADATA_DIR, $isReadOnly);
     $configuration->setMetadataCache($metadataStorage);
+
+    if ($isReadOnly) {
+      $configuration->setMetadataDriverImpl(new CacheOnlyMappingDriver($metadataStorage));
+    } else {
+      $configuration->setMetadataDriverImpl(new AnnotationDriver($annotationReader, [self::ENTITY_DIR]));
+    }
   }
 
   private function configureProxies(Configuration $configuration) {