Tracker isn't syncing

[ZoeHulme]

My blaze is receiving messages but won't connect to my phone and sync. When asked to enter the 4 digit code to connect it, it just gets stuck on that page and doesn't continue. My dashboard is not showing any paired device. I've followed advise but I'm at a loss now, please help! 

Moderator edit: Updated subject for clarity 

[SunsetRunner]

Is the device you are trying to sync to a supported device?

iOS: https://www.fitbit.com/content/assets/onezip/images/devices/Fitbit_SupportedDevices_iOS.pdf

Android: https://www.fitbit.com/content/assets/onezip/images/devices/Fitbit_SupportedDevices_Android.pdf

Windows: https://www.fitbit.com/content/assets/onezip/images/devices/Fitbit_SupportedDevices_Windows.pdf

[ZoeHulme]

Yes it is. It worked perfectly for two months then the time went very wrong. I tried to sync to fix it and forgot the connection, I know I prob shouldn't have. So I open the app and it says set up a device and the 4digit pin comes up ok, enter the no, but that is the page it gets suck on 

[Rich_Laue]

You've restarted the phone, and the tracker? I would go into the ph9nes Bluetooth sett8ngs and remove the tracker. The reason your receiving notices is because the tracker is still bonded to the phone. This bonding will also prevent it from conneconnecting t9 another device. 

Before we can set ii up we have to fix the sync issue.