letsencrypt error

2016-12-23 06:14:11,906:DEBUG:letsencrypt.cli:Root logging level set at 30
2016-12-23 06:14:11,908:INFO:letsencrypt.cli:Saving debug log to /var/log/letsencrypt/letsencrypt.log
2016-12-23 06:14:11,910:DEBUG:letsencrypt.cli:letsencrypt version: 0.4.1
2016-12-23 06:14:11,910:DEBUG:letsencrypt.cli:Arguments: []
2016-12-23 06:14:11,911:DEBUG:letsencrypt.cli:Discovered plugins: PluginsRegistry(PluginEntryPoint#webroot,PluginEntryPoint#null,PluginEntryPoint#manual,PluginEntryPoint#standalone)
2016-12-23 06:14:11,943:DEBUG:letsencrypt.cli:Requested authenticator  and installer
2016-12-23 06:14:11,943:DEBUG:letsencrypt.cli:Default Detector is Namespace(account='', agree_dev_preview=None, apache='', authenticator='', break_my_certs='', cert_path='/home/nick', chain_path=None, checkpoints=0, config_dir='', config_file=None, configurator='', csr='', debug='', domains=[], dry_run='', duplicate='', email='', expand='', fullchain_path=None, func=<function renew at 0x7f3a40b09140>, hsts=False, http01_port=0, ifaces='', init='', installer='', key_path='/home/nick', logs_dir='', manual='', manual_public_ip_logging_ok=False, manual_test_mode=False, nginx='', no_self_upgrade='', no_verify_ssl=False, noninteractive_mode='', os_packages_only='', prepare='', redirect=None, register_unsafely_without_email='', reinstall='', renew_by_default='', rsa_key_size=0, server='', staging='', standalone='', standalone_supported_challenges='tls-sni-01,http-01', store_false_vars={'--no-hsts': True, '--no-uir': True, <letsencrypt.cli.HelpfulArgumentParser object at 0x7f3a4062c550>: True, '--no-redirect': True}, strict_permissions='', text_mode='', tls_sni_01_port=0, tos='', uir=None, user_agent=None, verb='renew', verbose_count=0, version='', webroot='', webroot_map={}, webroot_path=[], work_dir='')
2016-12-23 06:14:11,962:WARNING:letsencrypt.cli:Attempting to renew cert from /etc/letsencrypt/renewal/triantos.com.conf produced an unexpected error: max() arg is an empty sequence. Skipping.
2016-12-23 06:14:12,028:DEBUG:letsencrypt.cli:Traceback was:
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/letsencrypt/cli.py", line 1015, in renew
    if _should_renew(lineage_config, renewal_candidate):
  File "/usr/lib/python2.7/dist-packages/letsencrypt/cli.py", line 286, in _should_renew
    if lineage.should_autorenew(interactive=True):
  File "/usr/lib/python2.7/dist-packages/letsencrypt/storage.py", line 647, in should_autorenew
    if self.ocsp_revoked(self.latest_common_version()):
  File "/usr/lib/python2.7/dist-packages/letsencrypt/storage.py", line 456, in latest_common_version
    return max(n for n in versions[0] if all(n in v for v in versions[1:]))
ValueError: max() arg is an empty sequence

2016-12-23 06:14:12,028:DEBUG:letsencrypt.cli:Exiting abnormally:
Traceback (most recent call last):
  File "/usr/bin/letsencrypt", line 9, in <module>
    load_entry_point('letsencrypt==0.4.1', 'console_scripts', 'letsencrypt')()
  File "/usr/lib/python2.7/dist-packages/letsencrypt/cli.py", line 1986, in main
    return config.func(config, plugins)
  File "/usr/lib/python2.7/dist-packages/letsencrypt/cli.py", line 1034, in renew
    len(renew_failures), len(parse_failures)))
Error: 1 renew failure(s), 0 parse failure(s)