Uninstall and reinstall Netflix app on Xbox 360 to fix Netflix show error code R8102-101 due to Netflix app is out of date.
Solution: Uninstall and reinstall Netflix app
Uninstall Netflix
Step 1: From Xbox 360 Dashboard, navigate to Apps > My Apps.
Step 2: Highlight Netflix app then press the X button for app details.
Step 3: Select Delete, press Yes to confirm.
Reinstall Netflix
Step 1: From Xbox 360 Dashboard, navigate to Apps.
Step 2: Select Netflix tile to download the app.
Step 3: Sign back in and try Netflix again.
Reference
Netflix Help Center: Netflix Error R8102-101