diff --git a/okhttp/src/main/java/io/grpc/okhttp/OkHttpClientStream.java b/okhttp/src/main/java/io/grpc/okhttp/OkHttpClientStream.java
index ffa4b316bf..9a299b595e 100644
--- a/okhttp/src/main/java/io/grpc/okhttp/OkHttpClientStream.java
+++ b/okhttp/src/main/java/io/grpc/okhttp/OkHttpClientStream.java
@@ -190,11 +190,14 @@ class OkHttpClientStream extends Http2ClientStream {
     }
 
     synchronized (lock) {
+      if (cancelSent) {
+        return;
+      }
       if (pendingData != null) {
         // Stream is pending start, queue the data.
         pendingData.add(new PendingData(buffer, endOfStream, flush));
       } else {
-        checkState(id() != 0, "streamId should be set");
+        checkState(id() != null, "streamId should be set");
         // If buffer > frameWriter.maxDataLength() the flow-controller will ensure that it is
         // properly chunked.
         outboundFlow.data(endOfStream, id(), buffer, flush);
diff --git a/okhttp/src/test/java/io/grpc/okhttp/OkHttpClientTransportTest.java b/okhttp/src/test/java/io/grpc/okhttp/OkHttpClientTransportTest.java
index cf81e9cce6..997d4adf6d 100644
--- a/okhttp/src/test/java/io/grpc/okhttp/OkHttpClientTransportTest.java
+++ b/okhttp/src/test/java/io/grpc/okhttp/OkHttpClientTransportTest.java
@@ -197,7 +197,7 @@ public class OkHttpClientTransportTest {
     startTransport(3, null, true, 1);
 
     MockStreamListener listener = new MockStreamListener();
-    clientTransport.newStream(method, new Metadata.Headers(), listener).request(1);
+    clientTransport.newStream(method, new Metadata(), listener).request(1);
     assertContainStream(3);
     frameHandler().headers(false, false, 3, 0, grpcResponseHeaders(), HeadersMode.HTTP_20_HEADERS);
     assertNotNull(listener.headers);