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If both the AUX and Dock LEDs are flashing on your system, it will usually let us know that it thinks there is a hardware issue with the speaker. As you have already tried the troubleshooting I would recommend when you see these LEDs flashing, what you will want to do is reach out to your local support team to discuss the service options available for your SoundDock.
You can find the contact information for your local support team at this link, by selecting your country/region and then the 'Contact Us' option at the bottom of the page.
I hope this helps!
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