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I recently obtained an iPhone XS and installed the App on it to sync my Zip FitBit to. On successful setup and sync of Zip on the iPhone using the App I was prompted to perform an update to the Zip. I replaced the battery in the Zip and reconnected to my iPhone. I performed the update to the Zip successfully as the progress bar indicated it was complete. I tried to sync the data and it no longer would transfer any data after the update. I tried for several minutes to connect and sync. The device is recognized but won't sync. The next morning I removed the battery and rebooted my phone and even installed the Windows App and tried to use the dongle. It sees the device prompts for the 4 digit code but fails to setup giving an error message. "com.fitbit.http error 400". Please advise of the fix for this issue so that I can restore functionality to my fitbit Zip as quickly as possible.
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