Sync not working

[elman23]

I have followed the provided tutorial to test the sync functionality, but I experience errors.

I launch the Sync Gateway version 2.8.3 and I execute the Android app in two emulators, but when saving the information entered in one of the apps I cannot see any syncronization, but I read the following error in the Sync Gateway log:

2021-11-04T14:21:38.029Z [DBG] WS+: c:#007 Incoming BLIP Request: MSG#5
2021-11-04T14:21:38.029Z [INF] SyncMsg: c:[2f4ad42] #5: Type:setCheckpoint Client:cp-1kgJ3LEaHMndYaAyzUJmptUw0g0=
2021-11-04T14:21:38.029Z [DBG] SyncMsg+: c:[2f4ad42] #5: Type:setCheckpoint   --> OK Time:96.8µs
2021-11-04T14:21:38.029Z [DBG] WSFrame+: c:#007 Push RPY#5
2021-11-04T14:21:38.029Z [DBG] WSFrame+: c:#007 Sending frame: RPY#5 (flags=       1, size=    9)
2021-11-04T14:22:05.103Z [DBG] WSFrame+: c:#009 Received frame: MSG#4!~ (flags=   11000, length=102)
2021-11-04T14:22:05.103Z [DBG] WS+: c:#009 Incoming BLIP Request: MSG#4!~
2021-11-04T14:22:05.103Z [INF] SyncMsg: c:[767d15f9] #4: Type:proposeChanges #Changes: 1
2021-11-04T14:22:05.103Z [WRN] c:[767d15f9] CheckProposedRev("user::demo@example.com") --> *errors.errorString GetWithXattr not implemented for walrus -- db.(*Database).CheckProposedRev() at crud.go:2257
2021-11-04T14:22:05.103Z [DBG] c:[767d15f9] Setting deltas=true property on proposeChanges response
2021-11-04T14:22:05.103Z [DBG] SyncMsg+: c:[767d15f9] #4: Type:proposeChanges   --> OK Time:132.4µs
2021-11-04T14:22:05.103Z [DBG] WSFrame+: c:#009 Push RPY#4!~
2021-11-04T14:22:05.103Z [DBG] WSFrame+: c:#009 Sending frame: RPY#4!~ (flags=   11001, size=   18)
2021-11-04T14:22:05.110Z [DBG] WSFrame+: c:#009 Received frame: MSG#5 (flags=       0, length=96)

How can I fix this problem?