Real Time Backup ERROR

Seafile Server
1

Hello,
I have an error during the real time backup, everything starts well and quickly it shows me that:
Any idea ?

[root@seafile-bkp seafile-server-latest]# ./seaf-backup-cmd.sh status
Total number of libraries: 1626
Number of synchronized libraries: 75
Number of libraries waiting for sync: 1547
Number of libraries syncing: 4
Number of libraries failed to sync: 0

List of syncing libraries:
030f1b0a-a2e8-404e-8491-c1d1a3eb7729
6dca57d8-c46f-4520-86c2-1358bc2b2beb
a6ae41c0-829c-45d7-b45d-57b6d1df1ae2
4b564a9d-ede1-4465-bb91-a0e7a01f65ed

List of libraries failed to sync:

And 5 seconds after :

[root@seafile-bkp seafile-server-latest]# ./seaf-backup-cmd.sh status
    Traceback (most recent call last):
      File "/opt/seafile/seafile-pro-server-6.3.7/seaf-backup-cmd.py", line 50, in <module>
        args.func(args)
      File "/opt/seafile/seafile-pro-server-6.3.7/seaf-backup-cmd.py", line 11, in show_backup_status
        ret_str = seafile_api.get_backup_status()
      File "/opt/seafile/seafile-pro-server-6.3.7/seafile/lib64/python2.7/site-packages/seaserv/api.py", line 1115, in get_backup_status
        return seafserv_threaded_rpc.get_backup_status()
      File "/opt/seafile/seafile-pro-server-6.3.7/seafile/lib64/python2.7/site-packages/pysearpc/client.py", line 110, in newfunc
        ret_str = self.call_remote_func_sync(fcall_str)
      File "/opt/seafile/seafile-pro-server-6.3.7/seafile/lib64/python2.7/site-packages/ccnet/rpc.py", line 75, in call_remote_func_sync
        req_id = self._start_service(client)
      File "/opt/seafile/seafile-pro-server-6.3.7/seafile/lib64/python2.7/site-packages/ccnet/rpc.py", line 36, in _start_service
        raise SearpcError("Error received: %s %s (In _start_service)" % (rsp.code, rsp.code_msg))
    pysearpc.common.SearpcError: Error received: 511 Unknown service (In _start_service)