diff --git a/src/Symfony/Component/Messenger/Tests/Transport/RedisExt/ConnectionTest.php b/src/Symfony/Component/Messenger/Tests/Transport/RedisExt/ConnectionTest.php
index 57eafa2c1db7..6dd7a0287b5e 100644
--- a/src/Symfony/Component/Messenger/Tests/Transport/RedisExt/ConnectionTest.php
+++ b/src/Symfony/Component/Messenger/Tests/Transport/RedisExt/ConnectionTest.php
@@ -186,6 +186,20 @@ public function testGetNonBlocking()
         $redis->del('messenger-getnonblocking');
     }
 
+    public function testJsonError()
+    {
+        $redis = new \Redis();
+
+        $connection = Connection::fromDsn('redis://localhost/json-error', [], $redis);
+
+        try {
+            $connection->add("\xB1\x31", []);
+        } catch (TransportException $e) {
+        }
+
+        $this->assertSame('Malformed UTF-8 characters, possibly incorrectly encoded', $e->getMessage());
+    }
+
     public function testMaxEntries()
     {
         $redis = $this->getMockBuilder(\Redis::class)->disableOriginalConstructor()->getMock();
diff --git a/src/Symfony/Component/Messenger/Transport/RedisExt/Connection.php b/src/Symfony/Component/Messenger/Transport/RedisExt/Connection.php
index 33d6057f6700..e1980221625e 100644
--- a/src/Symfony/Component/Messenger/Transport/RedisExt/Connection.php
+++ b/src/Symfony/Component/Messenger/Transport/RedisExt/Connection.php
@@ -248,6 +248,10 @@ public function add(string $body, array $headers, int $delayInMs = 0): void
                     'uniqid' => uniqid('', true),
                 ]);
 
+                if (false === $message) {
+                    throw new TransportException(json_last_error_msg());
+                }
+
                 $score = (int) ($this->getCurrentTimeInMilliseconds() + $delayInMs);
                 $added = $this->connection->zadd($this->queue, ['NX'], $score, $message);
             } else {
@@ -256,6 +260,10 @@ public function add(string $body, array $headers, int $delayInMs = 0): void
                     'headers' => $headers,
                 ]);
 
+                if (false === $message) {
+                    throw new TransportException(json_last_error_msg());
+                }
+
                 if ($this->maxEntries) {
                     $added = $this->connection->xadd($this->stream, '*', ['message' => $message], $this->maxEntries, true);
                 } else {