Double Tap Not Working

[WPCentral Question]

I have a Lumia 625 icon.
Wake up Double tap isn't working anymore, I use 'Preview for Developer' and I already update 'to 8.1 update 1', also yesterday a new OS version: 8.10.14157.200
Please help, I really like the Double Tap to Wake UP my phone, thanks

 

[xandros9]

Can you confirm the proximity sensor is working properly/is not obstructed? (such as the screen turning on and off properly during a call)

Also make sure its on, just in case.
And also try a soft reset first - press and hold power + volume down until it vibrates.