diff --git a/src/engines/html5/media-source/adapters/native-adapter.js b/src/engines/html5/media-source/adapters/native-adapter.js
index da5a2be20..07db3cdda 100644
--- a/src/engines/html5/media-source/adapters/native-adapter.js
+++ b/src/engines/html5/media-source/adapters/native-adapter.js
@@ -459,9 +459,9 @@ export default class NativeAdapter extends BaseMediaSourceAdapter {
     requestFilterPromise = requestFilterPromise || Promise.resolve(pkRequest);
     requestFilterPromise
       .then(updatedRequest => {
-        if (this._config.useSourceTag) {
+        if (this._sourceObj && this._config.useSourceTag) {
           const source = document.createElement('source');
-          const mimetype = this._sourceObj ? this._sourceObj.mimetype.toLowerCase() : 'application/dash+xml';
+          const mimetype = this._sourceObj.mimetype.toLowerCase();
           source.setAttribute('src', updatedRequest.url);
           source.setAttribute('type', mimetype);