diff --git a/libs/sparkpost-lib/src/main/java/com/sparkpost/transport/RestConnection.java b/libs/sparkpost-lib/src/main/java/com/sparkpost/transport/RestConnection.java
index c5330c9..0b2baee 100644
--- a/libs/sparkpost-lib/src/main/java/com/sparkpost/transport/RestConnection.java
+++ b/libs/sparkpost-lib/src/main/java/com/sparkpost/transport/RestConnection.java
@@ -184,8 +184,7 @@ private void sendData(HttpURLConnection conn, String data) throws SparkPostExcep
         // Send data. At this point connection to server may not be established,
         // but writing data to it will trigger the connection.
         try (DataOutputStream wr = new DataOutputStream(conn.getOutputStream())) {
-
-            wr.writeBytes(data);
+            wr.write(data.getBytes(DEFAULT_CHARSET));
             wr.flush();
         } catch (IOException ex) {
             throw new SparkPostException("Error sending request data:" + ex.toString());