Spo2 not working on Versa 4

[QuangD]

I installed everything: Spo2 app, Spo2 clock face. But on the screen away said : Couldn’t read Spo2.

Moderator edit: clarified subject.

[ManuFitbit]

A warm welcome to the community @QuangD. 

Thank you for taking the time to share the inquiry regarding your Versa 4. Sorry to know that you have difficulties to get SpO2 values.

Please keep the following in mind to make sure your Fitbit device successfully measures your SpO2:

• Your device doesn’t retroactively measure your SpO2 values. After you install the clock face, you’ll see dashed lines until after your next sleep session.
• Charge your Fitbit device to make sure it’s able to collect data throughout your entire sleep session. Note that you may have to charge your Fitbit device more often when using the SpO2 Signature clock face.
• Your Fitbit device must sync with the Fitbit app before the clock face updates. Note that it may take around an hour for your SpO2 values to appear after you sync your device. For troubleshooting syncing, see Why won't my Fitbit device sync?

• Turning off any clock face permissions can cause the clock face to stop functioning. To check these settings:

  1. With your Fitbit device nearby, open the Fitbit app on your phone or tablet.
  2. In the Fitbit app, tap the Today tab > your profile picture > your device image.
  3. Tap Clock Faces.
  4. Tap the SpO2 Signature clock face.
  5. Tap Permissions. Turn on any permissions you turned off.
  6. Tap Details when you're done making changes.

• Your Fitbit device must be able to consistently track your SpO2 data:

  • Make sure your device is in contact with your skin.

  • Your device should be snug but not constricting.

  • Tattooed skin can impact the accuracy of the red and infrared sensors on your Fitbit device.

For more information about SpO2, see: How do I track blood oxygen saturation (SpO2) with my Fitbit device? 

[QuangD]

Finally it’s working after I reset couple times.

Thank for your help.