diff --git a/src/ElasticSearch.php b/src/ElasticSearch.php
index 2b10385..5ef7f16 100644
--- a/src/ElasticSearch.php
+++ b/src/ElasticSearch.php
@@ -123,7 +123,7 @@ public function query($queryString, $type, $start = 0, $count = 10, $order = '_i
     /**
      * (Re)Generate the index for a given resource
      * @param IndexIterator|array $documents
-     * @return integer
+     * @throws ClientErrorResponseException
      */
     public function index($documents = []): int
     {
diff --git a/src/ElasticSearchIndexer.php b/src/ElasticSearchIndexer.php
index f405c6c..8c41c4d 100644
--- a/src/ElasticSearchIndexer.php
+++ b/src/ElasticSearchIndexer.php
@@ -22,6 +22,7 @@
 namespace oat\tao\elasticsearch;
 
 use Elasticsearch\Client;
+use Elasticsearch\Common\Exceptions\ClientErrorResponseException;
 use Psr\Log\LoggerInterface;
 use RuntimeException;
 use Iterator;
@@ -74,6 +75,7 @@ public function getIndexNameByDocument(IndexDocument $document): string
     /**
      * @param Iterator $documents
      * @return int The number of indexed documents
+     * @throws ClientErrorResponseException
      */
     public function buildIndex(Iterator $documents): int
     {
@@ -110,6 +112,10 @@ public function buildIndex(Iterator $documents): int
             if ($blockSize === self::INDEXING_BLOCK_SIZE) {
                 $clientResponse = $this->client->bulk($params);
 
+                if ($clientResponse['errors'] === true) {
+                    throw new ClientErrorResponseException($this->parseErrors($clientResponse));
+                }
+
                 $this->logger->debug('client response: '. json_encode($clientResponse));
 
                 $count += $blockSize;
@@ -121,7 +127,11 @@ public function buildIndex(Iterator $documents): int
         if ($blockSize > 0) {
             $clientResponse = $this->client->bulk($params);
 
-            $this->logger->debug('client response: '. json_encode($clientResponse));
+            if ($clientResponse['errors'] === true) {
+                throw new ClientErrorResponseException($this->parseErrors($clientResponse));
+            }
+
+            $this->logger->debug('client response: ' . json_encode($clientResponse));
 
             $count += $blockSize;
         }
@@ -141,7 +151,7 @@ public function deleteDocument($id): bool
             $deleteParams = [
                 'type' => '_doc',
                 'index' => $document['_index'],
-                'id' => $document['_id']
+                'id' => $document['_id'],
             ];
             $this->getClient()->delete($deleteParams);
 
@@ -154,6 +164,7 @@ public function deleteDocument($id): bool
     /**
      * @param array $ids
      * @param string $type
+     *
      * @return array
      */
     public function searchResourceByIds($ids = [])
@@ -214,4 +225,15 @@ private function extendBatch(string $action, string $indexName, IndexDocument $d
 
         return $params;
     }
+
+    private function parseErrors(array $clientResponse): string
+    {
+        $errors = '';
+        
+        foreach ($clientResponse['items'] as $response) {
+            $response = reset($response);
+            $errors .= $response['error']['reason'] . '; ';
+        }
+        return $errors;
+    }
 }
diff --git a/test/ElasticSearchIndexerTest.php b/test/ElasticSearchIndexerTest.php
index e12cbe5..850367f 100644
--- a/test/ElasticSearchIndexerTest.php
+++ b/test/ElasticSearchIndexerTest.php
@@ -23,6 +23,7 @@
 namespace oat\tao\test\elasticsearch;
 
 use Elasticsearch\Client;
+use Elasticsearch\Common\Exceptions\ClientErrorResponseException;
 use oat\generis\test\TestCase;
 use oat\oatbox\log\LoggerService;
 use oat\tao\elasticsearch\ElasticSearchIndexer;
@@ -30,6 +31,7 @@
 use oat\tao\model\search\index\IndexDocument;
 use oat\tao\model\TaoOntology;
 use ArrayIterator;
+use PHPUnit\Framework\MockObject\MockObject;
 
 /**
  * ElasticSearchIndexerTest
@@ -88,6 +90,106 @@ public function testGetIndexNameByDocumentForUnclassifieds(): void
         $this->assertSame(IndexerInterface::UNCLASSIFIEDS_DOCUMENTS_INDEX, $indexName);
     }
 
+    public function testBuildIndexBulkErrorResponseAfter100(): void
+    {
+        $this->expectException(ClientErrorResponseException::class);
+        $this->expectExceptionMessage('some reason; some other reason');
+
+        $document = $this->createMock(IndexDocument::class);
+        $document->expects($this->any())
+            ->method('getBody')
+            ->willReturn([
+                'type' => [
+                    TaoOntology::CLASS_URI_ITEM,
+                ],
+            ]);
+
+        $document->expects($this->any())
+            ->method('getId')
+            ->willReturn('some_id');
+
+        $this->client
+            ->expects($this->atMost(100))
+            ->method('bulk')
+            ->willReturn([
+                'errors' => true,
+                'items' => [
+                    [
+                        [
+                            'error' => [
+                                'reason' => 'some reason',
+                            ],
+                        ],
+                    ],
+                    [
+                        [
+                            'error' => [
+                                'reason' => 'some other reason',
+                            ],
+                        ],
+                    ],
+                ],
+            ]);
+
+        $iterator = $this->createIterator($this->getMultipleDocs($document, 101));
+
+
+        $this->sut->buildIndex($iterator);
+    }
+
+    private function getMultipleDocs(MockObject $doc, $quantity)
+    {
+        $bigArray = [];
+        for ($i = 1; $i <= $quantity; $i++) {
+            array_push($bigArray, $doc);
+        }
+
+        return $bigArray;
+    }
+
+    public function testBuildIndexBulkErrorResponse(): void
+    {
+        $this->expectException(ClientErrorResponseException::class);
+        $this->expectExceptionMessage('some reason; some other reason');
+        $document = $this->createMock(IndexDocument::class);
+        $document->expects($this->any())
+            ->method('getBody')
+            ->willReturn([
+                'type' => [
+                    TaoOntology::CLASS_URI_ITEM,
+                ],
+            ]);
+
+        $document->expects($this->any())
+            ->method('getId')
+            ->willReturn('some_id');
+
+        $this->client
+            ->method('bulk')
+            ->willReturn([
+                'errors' => true,
+                'items' => [
+                    [
+                        [
+                            'error' => [
+                                'reason' => 'some reason',
+                            ],
+                        ],
+                    ],
+                    [
+                        [
+                            'error' => [
+                                'reason' => 'some other reason',
+                            ],
+                        ],
+                    ],
+                ],
+            ]);
+        $iterator = $this->createIterator([$document]);
+
+        $this->sut->buildIndex($iterator);
+    }
+
     public function testBuildIndex(): void
     {
         $document = $this->createMock(IndexDocument::class);