My robotic vacuum cleaner shows error E21, warning triangle and Play button are blinking

Last updated 06/04/2020 11:23


  • My robot shows error message E21
  • Warning triangle and Play button are blinking after the robot has been in the charger

Applies to

  • robotic vacuum cleaner


1. Update the robot software via the app or via the website dedicated download link

2. If the problem persists after the update:

  • Check if both batteries are properly connected and reset the robot by unplugging the batteries and wait 10 seconds. Reinstall the connectors and check if the problem is resolved.
  • If not, then you may need to replace both battery packs to remove this error code.
  • Put it back in the charging stand and restart it after charging is complete.
    AEG offers 6 months warranty on batteries.


  • The error code means that the battery charge is not completed normally or that charging has taken too long.
  • The reason may be that the batteries are worn or otherwise defective.
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