Leopard, iTunes & Airport Express: An unknown error occurred (-3256)

You may find you get the following problem when trying to stream music to multiple speakers. Streaming to either local computer OR your airport express works, but when you try to stream both, you get an error message that looks like this:

“An error occurred while connecting to the remote speaker ‘speaker_name’. An unknown error occurred (-3256).”

This is most likely caused by a firewall issue. If you’re running Tiger, then there’s a fix here. If, however, you’re running Leopard, then it’s a little different:

1. Open System Preferences
2. Click Security
3. Click Firewall
4. Either:
a. “Allow all incoming connections” – but I don’t recommend this, so
b. “Set access for specific services and applications”. Click the + symbol, then find iTunes in your Applications folder. Then set its permission to Allow incoming connections.

You should now be able to stream to multiple sets of speakers. Whilst you’re playing about in the firewall settings, click Advanced and enable the stealth mode, which seems to be off by default. You should also check that logging is enabled, as it’s possible that the change to your firewall settings will interfere with other applications you have installed.


  1. Jamie, I got excactly the same thing! (Except that the streaming works some of the time and then falls out and back in all the time, which is really annoying…)

    We are all ready running version 8.0.2, it should have been fixed by Appple long time ago…

  2. I have tried ALL the recommended fixes (Airport Express firmware OK at 6.3, IPv6 either on automatic or off entirely, and setting Firewall as recommended, but continue to get the -3256 error. Wish someone would crack this nut completely. Grrrrr!

  3. One more thing to try: make sure IPv6 is turned on. Here’s how with Leopard (10.5.4):
    System Preferences > Network > Airport > Advanced… > TCP/IP > Configure IPv6 : Automatically.

    I was pulling my hair out until someone on another site recommended this.

  4. You’re welcome Shelley!

    Tony.. not sure what to suggest. Have you done a complete factory reset on the AE?

    When the AE is synced up to your wireless, open the Airport admin utility and do the manual setup for your AE – it’ll show you a status of it and might indicate if anything is skewhiff. You could also try turning on Interference Robustness. But really I’m just guessing here.. !

  5. i did as above and still get the same error… my mac is going out the window soon! bloody thing!

  6. Thank you for posting this. I’ve been troubleshooting my airport expresses like crazy, resetting all the routers, etc. – this fixed it. Thank you!

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