If the Firstbeat Life application gives the following error message during the synchronisation phase of the measurement: "Data synchronisation from device failed. No data received from sensor as response to read file request".
To solve the issue, remove the Firstbeat Life app from your phone and reinstalled through the application store.
Please note! Do not release the Bodyguard 3 pairing from the app when you are reinstalling the application. This will clear the device memory and the measurement will be lost.
If you need any further help with this, don't hesitate to contact Firstbeat Support.