Hi, if the connection started misbehaving after the update, it is caused by a regression in this last FitBit uppate - according to the Fitbit support, there’s a bug in the Fitbit app which broke access to local webserver on the phone, so there’s no way for Sleep as Android to communicate with the watch.
The advice is to either downgrade the Fitbit app to version 3.58 or to wait for an update.
(Softpedia - https://mobile.softpedia.com/apk/fitbit/3.58/, install at your own risk, but they claim it’s safe)Let us know, please, if downgrading helps you.