1. Make sure that you're using the original charging cable that came with the Mighty. Many other USB-to-headphone jack cables, including the iPod Shuffle charging cable, are incompatible with the Mighty. 2. Make sure that there isn't water or sweat residue on the end of the charging cable or in/around Mighty's headphone jack. If there is any residue, use a cue tip to clean it. 3. Try a second charging block and power outlet to ensure that neither of those are causing the issue.
If you're still unable to get the LED to light up, please email us at firstname.lastname@example.org and we'll respond within one business day to help you troubleshoot.