CurrentTime get empty exception

My code as following.But I got exception empty and I think it's because that self.service_instance.CurrentTime get empty exception.So I can't figure out how it occurred and I wonder why CurrentTime get wrong.
`
def _keep_alive_config(self):
while True:
self._recollect("keep_alive_config",
self.service_instance.CurrentTime)
time.sleep(5)

def _recollect(self, entity_name, func, args=()):
i = 0
while True:
i += 1
try:
return func(*args)
except Exception as ex:
if len(ex.args) > 1 and ex.args[0] in [10053, 10054,
10060]:
self.logger.info(
"Collect %s failed.\n" % entity_name + str(ex.args[0]))
if i <= 3:
warning = 'A network exception occurred while '
'collecting %s, wait 30 seconds '
'and retry', entity_name
self.logger.warning(warning)
time.sleep(30)
else:
self.logger.error(
'Terminate collecting due to'
' network anomalies!!!!!!')
self.logger.error(ex)
else:
self.logger.error(
'Stop collect information of %s due to'
' error occurd.' % entity_name)
self.logger.error(ex) #Exception is empty?
break`

The log file shows error as following:
[2020-06-03 20:41:00,156] [_recollect:282] Stop collect information of keep_alive_config due to error occurd.
[2020-06-03 20:41:00,156] [_recollect:285]
[2020-06-03 20:41:05,655] [_recollect:282] Stop collect information of keep_alive_config due to error occurd.
[2020-06-03 20:41:05,655] [_recollect:285]
[2020-06-03 20:41:11,169] [_recollect:282] Stop collect information of keep_alive_config due to error occurd.
[2020-06-03 20:41:11,169] [_recollect:285]
[2020-06-03 20:41:16,674] [_recollect:282] Stop collect information of keep_alive_config due to error occurd.
[2020-06-03 20:41:16,674] [_recollect:285]
[2020-06-03 20:41:22,191] [_recollect:282] Stop collect information of keep_alive_config due to error occurd.
[2020-06-03 20:41:22,197] [_recollect:285]
[2020-06-03 20:41:27,706] [_recollect:282] Stop collect information of keep_alive_config due to error occurd.
[2020-06-03 20:41:27,712] [_recollect:285]

Start with the _keep_alive_config and _recollect entry points shown in the report, then reproduce the self.service_instance.CurrentTime call with the same setup. Inspect the caught exception and logging output; done means the failure has a documented cause and the issue specifies a reproducible fix or diagnostic change.