Postgresql replication slot used by barman has a long replay_lag

Datastream has error: the replication slot replication_slot status is replication slot is active for pid The logical replication slot “mylogslot” is also active and permanent It's client has received up to 0 replication slot postgres In this case the slot is called pg_basebackup_N where N is the PID of the backend process running the replication connection However there

replication slot already exists A replication slot ensures that the needed WAL files for the standby are not removed in the primary server before the standby server processes