letsencrypt error

2015-11-06 09:15:12,195:DEBUG:letsencrypt.cli:Root logging level set at 30
2015-11-06 09:15:12,197:INFO:letsencrypt.cli:Saving debug log to /var/log/letsencrypt/letsencrypt.log
2015-11-06 09:15:12,198:DEBUG:letsencrypt.cli:letsencrypt version: 0.0.0.dev20151104
2015-11-06 09:15:12,198:DEBUG:letsencrypt.cli:Arguments: ['--agree-dev-preview', '--webroot-path', '/usr/share/nginx/mober.net/html/', '--server', 'https://acme-v01.api.letsencrypt.org/directory']
2015-11-06 09:15:12,199:DEBUG:letsencrypt.cli:Discovered plugins: PluginsRegistry(PluginEntryPoint#apache,PluginEntryPoint#webroot,PluginEntryPoint#null,PluginEntryPoint#manual,PluginEntryPoint#standalone)
2015-11-06 09:15:12,204:DEBUG:letsencrypt.cli:Requested authenticator None and installer None
2015-11-06 09:15:12,395:DEBUG:letsencrypt.plugins.disco:No installation (PluginEntryPoint#apache):
Traceback (most recent call last):
  File "/root/.local/share/letsencrypt/local/lib/python2.7/site-packages/letsencrypt/plugins/disco.py", line 103, in prepare
    self._initialized.prepare()
  File "/root/.local/share/letsencrypt/local/lib/python2.7/site-packages/letsencrypt_apache/configurator.py", line 145, in prepare
    raise errors.NoInstallationError
NoInstallationError
2015-11-06 09:15:12,396:DEBUG:letsencrypt.plugins.webroot:Creating root challenges validation dir at /usr/share/nginx/mober.net/html/.well-known/acme-challenge
2015-11-06 09:15:12,406:DEBUG:letsencrypt.display.ops:Multiple candidate plugins: * webroot
Description: Webroot Authenticator
Interfaces: IAuthenticator, IPlugin
Entry point: webroot = letsencrypt.plugins.webroot:Authenticator
Initialized: <letsencrypt.plugins.webroot.Authenticator object at 0x7f3380257890>
Prep: True

* standalone
Description: Automatically use a temporary webserver
Interfaces: IAuthenticator, IPlugin
Entry point: standalone = letsencrypt.plugins.standalone:Authenticator
Initialized: <letsencrypt.plugins.standalone.Authenticator object at 0x7f33802579d0>
Prep: True
2015-11-06 09:15:19,661:DEBUG:letsencrypt.cli:Selected authenticator <letsencrypt.plugins.webroot.Authenticator object at 0x7f3380257890> and installer None
2015-11-06 09:15:19,737:DEBUG:letsencrypt.cli:Picked account: <Account(9d8dd4e40656d99ba9cd8370f80dbed2)>
2015-11-06 09:15:19,738:DEBUG:root:Sending GET request to https://acme-v01.api.letsencrypt.org/directory. args: (), kwargs: {}
2015-11-06 09:15:19,755:INFO:requests.packages.urllib3.connectionpool:Starting new HTTPS connection (1): acme-v01.api.letsencrypt.org
2015-11-06 09:15:20,521:DEBUG:requests.packages.urllib3.connectionpool:"GET /directory HTTP/1.1" 200 263
2015-11-06 09:15:20,523:DEBUG:root:Received <Response [200]>. Headers: {'Content-Length': '263', 'Expires': 'Fri, 06 Nov 2015 09:15:11 GMT', 'Strict-Transport-Security': 'max-age=604800', 'Server': 'nginx', 'Connection': 'keep-alive', 'Pragma': 'no-cache', 'Cache-Control': 'max-age=0, no-cache, no-store', 'Date': 'Fri, 06 Nov 2015 09:15:11 GMT', 'X-Frame-Options': 'DENY', 'Content-Type': 'application/json', 'Access-Control-Allow-Origin': '*', 'Replay-Nonce': 'dCR6GjNIXBX-5BdcH4tJBUwuib3SLcIp8yzPTXxiNUo'}. Content: '{"new-authz":"https://acme-v01.api.letsencrypt.org/acme/new-authz","new-cert":"https://acme-v01.api.letsencrypt.org/acme/new-cert","new-reg":"https://acme-v01.api.letsencrypt.org/acme/new-reg","revoke-cert":"https://acme-v01.api.letsencrypt.org/acme/revoke-cert"}'
2015-11-06 09:15:20,524:DEBUG:acme.client:Received response <Response [200]> (headers: {'Content-Length': '263', 'Expires': 'Fri, 06 Nov 2015 09:15:11 GMT', 'Strict-Transport-Security': 'max-age=604800', 'Server': 'nginx', 'Connection': 'keep-alive', 'Pragma': 'no-cache', 'Cache-Control': 'max-age=0, no-cache, no-store', 'Date': 'Fri, 06 Nov 2015 09:15:11 GMT', 'X-Frame-Options': 'DENY', 'Content-Type': 'application/json', 'Access-Control-Allow-Origin': '*', 'Replay-Nonce': 'dCR6GjNIXBX-5BdcH4tJBUwuib3SLcIp8yzPTXxiNUo'}): '{"new-authz":"https://acme-v01.api.letsencrypt.org/acme/new-authz","new-cert":"https://acme-v01.api.letsencrypt.org/acme/new-cert","new-reg":"https://acme-v01.api.letsencrypt.org/acme/new-reg","revoke-cert":"https://acme-v01.api.letsencrypt.org/acme/revoke-cert"}'
2015-11-06 09:15:20,525:DEBUG:letsencrypt.display.ops:No installer, picking names manually
2015-11-06 09:15:25,320:DEBUG:letsencrypt.cli:Exiting abnormally:
Traceback (most recent call last):
  File "/root/.local/share/letsencrypt/bin/letsencrypt", line 11, in <module>
    sys.exit(main())
  File "/root/.local/share/letsencrypt/local/lib/python2.7/site-packages/letsencrypt/cli.py", line 1138, in main
    return args.func(args, config, plugins)
  File "/root/.local/share/letsencrypt/local/lib/python2.7/site-packages/letsencrypt/cli.py", line 490, in obtaincert
    _auth_from_domains(le_client, config, domains, plugins)
  File "/root/.local/share/letsencrypt/local/lib/python2.7/site-packages/letsencrypt/cli.py", line 310, in _auth_from_domains
    lineage = _treat_as_renewal(config, domains)
  File "/root/.local/share/letsencrypt/local/lib/python2.7/site-packages/letsencrypt/cli.py", line 230, in _treat_as_renewal
    config, domains)
  File "/root/.local/share/letsencrypt/local/lib/python2.7/site-packages/letsencrypt/cli.py", line 204, in _find_duplicative_certs
    candidate_names = set(candidate_lineage.names())
  File "/root/.local/share/letsencrypt/local/lib/python2.7/site-packages/letsencrypt/storage.py", line 438, in names
    with open(target) as f:
TypeError: coercing to Unicode: need string or buffer, NoneType found