postgresql streaming replication -- continuous archiving?

im trying to set up streaming replication, but for some reason when i update the database on the master, the changes are not reflected on the standby server UNTIL i restart the postgresql service on the master. (i see new xlog files in master server but these do not get synced to the standby server). when i restart the service on master, i finally see new files added to my shared wal_archive folder

the only way I can make it sync automatically is if i set the archive_timeout.

Master:

   wal_level = 'hot_standby'            # minimal, archive, hot_standby, or logical
    archive_mode = on       # allows archiving to be done
                    # (change requires restart)
    archive_command = 'copy "%p" "\\\\VBOXSVR\\wal_archive\\%f"'
    max_wal_senders = 3     # max number of walsender processes
                    # (change requires restart)
    wal_keep_segments = 10      # in logfile segments, 16MB each; 0 disables

pb_hba.conf

host    replication  postgres    slaveip/32      trust