Unable to Pair Fitbit Flex (com.fitbit.HTTP error 400)

[LocalHero]

I have been attempting to pair my Flex for the better part of 2 days with no luck. Each time, I get "com.fitbit.HTTP error 400" in the app, or "An error has occurred" on PC/Mac Here is what I have tried so far in many different orders:

- Make sure Flex is fully charged

- Update app

- Logout and login again

- Force quit app

- Turn bluetooth off/on

- Reboot phone

- Restart Flex

- Uninstall/reinstall app

- Attempt to pair with Mac app

- Attempt to pair with Windows app

The Flex appears to be working as expected. It vibrates when I tap it during the pair process, but it always fails.

Does anyone have any idea what's going on here? I feel like I have run out of options at this point. Would love a little help.

I have an iPhone 6s running iOS 11.3.1 with Fitbit version iOS 2.51.

[MarcoGFitbit]

Hello @LocalHero, thanks for joining the Fitbit Community, it's great to have you on board. 

I appreciate you have brought this to my attention and for letting me know the troubleshooting steps you've tried so far. At this moment, I've contacted our Support team on your behalf to look into this issue further and provide you with some options. Please keep an eye on your email inbox for further instructions.

In case you need anything else, please feel free to reply as well. Happy stepping.

[Jenwolemmoo]

I have exactly the same problem on an iPhone 5c. Have you managed to resolve? Thanks 

[LocalHero]

Jenwolemmoo, I haven't heard anything back from support yet, so nothing has been resolved. I'll reply back to this thread when I get a response.