NOTE: Factory restoring a Wemo device is different from rebooting your Wemo. Rebooting your Wemo does not remove any custom settings and can help in simple troubleshooting.
How to factory restore the Wemo WSP100
Step 1: Press and hold the power button down for 5 seconds.
Step 2: Continue to hold the power button down until the status light begins to blink white.
Step 2: Continue to hold the power button down until the status light begins to blink white.
Once the Wemo WSP100 is successfully factory restored, you may add the Wemo back to the Apple® Home app.
Related Article:
How to set up the Wemo WSP100