Charge 5 not syncing after update

[linuxdummy]

I have a fitbit charge 5 that has been working properly for a long time.  Last week the fitbit app updated to 4.06 and the charge 5 stopped syncing the time and etc with iphone. I found a number of things on the web to try, such as restarting the app, uninstall and reinstall the app, reset the charge 5, unpairing and re pairing the charge 5 but it won't pair now.  The 4 digits are displayed on the watch and enter them in the app and it fails.  The last thing I found was to factory reset the watch which I did and it still won't pair, get the numbers and enter them but fails to pair.  I installed fitbit (version 4.06) on another iphone and have the same problem on it .  Of course now the charge  5 won't do anything until it pairs with the app.  Is there anyway to install the previous version of the fitbit app or some other way to get my fitbit to work?

Moderator edit: edited title to clarity

[CrisVillaFitbit]

Hi, @linuxdummy Welcome to the community.

Thanks for informing me about this situation in regard to the set up of your Charge 5.

I appreciate you following these steps to solve the situation, there are certain requirements for the device to set up which are included in this article, under either the IPhones or Android phones part.

Let me know once you have double checked and tell me how it goes.

[linuxdummy]

I've been through all those steps with the last thing I tried being resetting the charge 5 to factory settings.  Now it doesn't pair so there is nothing else I can find to do.  When attempting to add the device the charge 5 shows the 4 digits and when entered into the app after a wait get a message that the numbers aren't valid, try again.  Retried many times.  Last night I dug out an old iphone and installed the fitbit app which was older than 4.06 due to the ios level.  With that level app it wouldn't even attempt to pair.  So I updated the IOS to 15.8, the latest for that old phone and still wouldn't attempt to pair.  Next the fitbit app would update and it updated to 4.06.  The old phone does the same as the other two iphones I've tried, that being the charge 5 provides the 4 digits for pairing and when entered get the error message from the app that the number is invalid.  The charge 5 was working properly on Dec. 15.  The battery had to be recharged and after that the time wouldn't update and trying to sync would show the progress bar move to about three quarters across the screen on the watch and then fail with no message.  At that point in time notifications were still sent to the charge 5.  Maybe something is wrong with the charge 5 that a factory reset doesn't fix.  As it stands now there's nothing else that I can find to do to the charge 5 as it requires pairing with the app.  I've tried the three button reset on the cable many times too.  

[linuxdummy]

I've been trying many different things to get the charge 5 paired without success.  I found that the internet must be available in order to attempt to pair the charge 5 and now am wondering if somewhere this charge 5 is in database and for some reason the fitbit app won't allow it to be paired.  Possibly some 'security' added to prevent a stolen device from being used.  This morning I created a Google account and moved the fitbit account to the google account and still can't pair.  Anyone have any ideas?

[linuxdummy]

I just got off the phone with support and being turned over to the warranty folks.  From searching on general problems pairing fitbits this seems to be a problem that can be caused by changing your password.  Did change my password recently.  Not sure what to expect going forward.  Hopefully get a replacement but seems some get a 50% on a new one.  

[linuxdummy]

So the warranty department offers me a 35% discount on a new device if bought directly from Fitbit/Google.  In my opinion the actual problem is that the device has been flagged in a database and rather than resetting the flag the solution is for me to buy a new device and from searching the web I'm not the only one and it isn't just the charge 5 as there are other models no longer pairing.  This may not be intentional, rather the result of some security measures that erroneously flags a device as stolen or some other suspicious state or a 'bug' in some code.