Unable to reserve slice

I'm trying to reserve the slice, but I'm encountering an error. I would greatly appreciate any help you can provide.

SITE_NAME = MASS
Slice Fail: unconverted data remains:  +0000

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
File <timed exec>:6

File /opt/conda/lib/python3.11/site-packages/fabrictestbed_extensions/fablib/slice.py:1992, in Slice.submit(self, wait, wait_timeout, wait_interval, progress, wait_jupyter, post_boot_config, wait_ssh, extra_ssh_keys)
   1988     FABRICSSHKey.get_key_length(ssh_key)
   1989 (
   1990     return_status,
   1991     slice_reservations,
-> 1992 ) = self.fablib_manager.get_slice_manager().create(
   1993     slice_name=self.slice_name,
   1994     slice_graph=slice_graph,
   1995     ssh_key=ssh_keys,
   1996 )
   1997 if return_status == Status.OK:

File /opt/conda/lib/python3.11/site-packages/fabrictestbed/slice_manager/slice_manager.py:217, in SliceManager.create(self, slice_name, ssh_key, topology, slice_graph, lease_end_time)
    215     return Status.INVALID_ARGUMENTS, SliceManagerException("Invalid arguments - lease_end_time")
--> 217 if self.__should_renew():
    218     self.__load_tokens()

File /opt/conda/lib/python3.11/site-packages/fabrictestbed/slice_manager/slice_manager.py:102, in SliceManager.__should_renew(self)
    100 created_at = self.tokens.get(CredmgrProxy.CREATED_AT, None)
--> 102 created_at_time = datetime.strptime(created_at, CredmgrProxy.TIME_FORMAT)
    103 now = datetime.utcnow()

File /opt/conda/lib/python3.11/_strptime.py:567, in _strptime_datetime(cls, data_string, format)
    565 """Return a class cls instance based on the input string and the
    566 format string."""
--> 567 tt, fraction, gmtoff_fraction = _strptime(data_string, format)
    568 tzname, gmtoff = tt[-2:]

File /opt/conda/lib/python3.11/_strptime.py:352, in _strptime(data_string, format)
    351 if len(data_string) != found.end():
--> 352     raise ValueError("unconverted data remains: %s" %
    353                       data_string[found.end():])
    355 iso_year = year = None

ValueError: unconverted data remains:  +0000

During handling of the above exception, another exception occurred:

NameError                                 Traceback (most recent call last)
File <timed exec>:11

NameError: name 'traceback' is not defined