diff --git a/dom/html/HTMLMediaElement.cpp b/dom/html/HTMLMediaElement.cpp
index 584b3592be3c..7f21961c1ee7 100644
--- a/dom/html/HTMLMediaElement.cpp
+++ b/dom/html/HTMLMediaElement.cpp
@@ -1695,6 +1695,7 @@ void HTMLMediaElement::NoSupportedMediaSourceError(const nsACString& aErrorDetai
   mErrorSink->SetError(MEDIA_ERR_SRC_NOT_SUPPORTED, aErrorDetails);
   ChangeDelayLoadStatus(false);
   UpdateAudioChannelPlayingState();
+  RejectPromises(TakePendingPlayPromises(), NS_ERROR_DOM_MEDIA_NOT_SUPPORTED_ERR);
 }
 
 typedef void (HTMLMediaElement::*SyncSectionFn)();
diff --git a/dom/html/HTMLMediaElement.h b/dom/html/HTMLMediaElement.h
index b9a341eb0599..df94077565a2 100644
--- a/dom/html/HTMLMediaElement.h
+++ b/dom/html/HTMLMediaElement.h
@@ -956,6 +956,7 @@ protected:
   void AbortExistingLoads();
 
   /**
+   * This is the dedicated media source failure steps.
    * Called when all potential resources are exhausted. Changes network
    * state to NETWORK_NO_SOURCE, and sends error event with code
    * MEDIA_ERR_SRC_NOT_SUPPORTED.