Fitbit Ionic not syncing to iPhone

[DGR2]

My iPhone and Ionic worked together well for around 5 or 6 months.  However, just over a week ago, my Ionic and iPhone stopped syncing, and I frequently had a message to save there was no internet connection.

Having read some of the help advice, I ended up carrying out the factory reset.  However, when trying to re-connect my Ionic, my iPhone suggested it had connected with my Ionic, but no four digit code appeared on my Ionic.

Since then I have tried the various suggestions, hard reset of iPhone, turning bluetooth on and off, ensuring my iPhone forgets my Ionic as a device, and tried to add my ionic again, but every time I get no further than the 'Not working' message via the app.  I have reset my watch a few times now by pressing the left and lower-right buttons and it is always charging whenever I try this.  Nothing seems to work, can anyone help?  Cheers, Dave   

Moderator edit: updated subject for clarity

[MarreFitbit]

Welcome to the Fitbit Community @DGR2, hope you're doing great!  Thanks for already troubleshooting this inconvenience between your iPhone and your Fitbit Ionic, nice way to go! 

Well, this usually happens when you performed a factory reset without before unpairing the device. Usually you should unpair your Ionic, forget Bluetooth (both Ionic and Ionic (Classic)) and perform the factory reset. To solve this issue follow these steps (some of them you already tried, but let's cover everything):

1. Unpair your Ionic from your Fitbit app (Remove This Ionic).
2. Unpair from Bluetooth both Ionic and Ionic (classic).
3. Force quit the Fitbit app.
4. Turn off the Bluetooth.
5. Shut off your phone and turn it on after 1-2 minutes.
6. Turn on the Bluetooth.
7. Make sure that your Fitbit app is up-to-date 
8. Setup your device again.
9. If there is no connection, restart your Fitbit Ionic.

If you can't get started with your Fitbit device, usually a missing requirement is the cause. Carefully review the requirements below:

• Note that you can't set up your Fitbit device from your phone's Bluetooth screen; you must open the Fitbit app and follow the on-screen instructions.
• The Fitbit app needs to be updated. 
• The software on your phone is up to date. To see if an update is waiting to be installed:
  • iOS—Tap Settings > General > Software Update.
• The Bluetooth setting on your phone or tablet is on. To find it:
  • iOS—Tap Settings > Bluetooth.

After making sure about that, try setting up your Ionic again.

Give this a go and let me know how it goes! 

[DGR2]

I have tried this a few times.  Every time I get as far as the Fitbit providing the code.  It flashes up incredibly quickly, and then disappears just as quick, and when it enter it on my phone, it thinks for a short while and then I get a message saying 'There was a problem connecting with your tracker. Please try again.'  If I then click the 'Not working?' link it just takes me back to the start.

I was going to try deleting the fitbit app and re-installing, do you think that might help?