diff --git a/src/server/chromium/crPage.ts b/src/server/chromium/crPage.ts
index 6573d0e611..cb130c4419 100644
--- a/src/server/chromium/crPage.ts
+++ b/src/server/chromium/crPage.ts
@@ -743,7 +743,8 @@ class FrameSession {
       return;
     const buffer = Buffer.from(payload.data, 'base64');
     this._videoRecorder.writeFrame(buffer, payload.metadata.timestamp!);
-    this._client.send('Page.screencastFrameAck', {sessionId: payload.sessionId});
+    // The target may be closed before receiving the ack.
+    this._client.send('Page.screencastFrameAck', {sessionId: payload.sessionId}).catch(() => {});
   }
 
   async _startScreencast(screencastId: string, options: types.PageScreencastOptions): Promise<void> {
diff --git a/test/screencast.spec.ts b/test/screencast.spec.ts
index b9a095d0ce..dfe4da5501 100644
--- a/test/screencast.spec.ts
+++ b/test/screencast.spec.ts
@@ -193,8 +193,7 @@ describe('screencast', suite => {
 
   it('should capture navigation', test => {
     test.flaky(options.CHROMIUM && MAC);
-    test.flaky(options.FIREFOX && LINUX && !options.HEADLESS);
-    test.flaky(options.FIREFOX && WIN);
+    test.flaky(options.FIREFOX);
     test.flaky(options.WEBKIT);
   }, async ({page, tmpDir, server, videoPlayer, toImpl}) => {
     const videoFile = path.join(tmpDir, 'v.webm');