Try resetting the dock.
Did it work before?
Did it work before you updated the iOS?
- Inspect the dock connector on the iPod for bent or missing contacts, foreign material, corroded contacts, broken, missing or cracked plastic.
Sometimes an iOPS update breaks compatibility.
Does the dock manufacturer say it will work with your model iPod and its iOS?
Is there a firmware update available for your dock?
Sometimes this works:
- Reset the iOS device. Nothing will be lost
Reset iOS device: Hold down the On/Off button and the Home button at the same time for at
least ten seconds, until the Apple logo appears.
- Reset all settings
Go to Settings > General > Reset and tap Reset All Settings.
All your preferences and settings are reset. Information (such as contacts and calendars) and media (such as songs and videos) aren’t affected.
- Restore from backup. See:
- Restore to factory settings/new iOS device.