PluginError: Unable to add title

Hi,

I’m using the client to renew the certificates of three groups of domains. It work well for the first two groups, but fails on the third. When I say “fail”, I mean the client exits with an error status code, and the following lines are displayed BUT the certificates are correctly generated.

2015-12-15 10:03:10,703:INFO:letsencrypt_apache.configurator:Deploying Certificate to VirtualHost /etc/apache2/sites-available/static.ssl.conf
2015-12-15 10:03:10,705:DEBUG:letsencrypt_apache.configurator:Apache version is 2.4.7
2015-12-15 10:03:10,726:ERROR:letsencrypt.reverter:Unable to finalize checkpoint - adding title
2015-12-15 10:03:10,730:DEBUG:letsencrypt.error_handler:Encountered exception:
Traceback (most recent call last):
  File "~/.local/share/letsencrypt/local/lib/python2.7/site-packages/letsencrypt/client.py", line 378, in deploy_certificate
    self.installer.save("Deployed Let's Encrypt Certificate")
  File "~/.local/share/letsencrypt/local/lib/python2.7/site-packages/letsencrypt_apache/augeas_configurator.py", line 135, in save
    raise errors.PluginError(str(err))
PluginError: Unable to add title

2015-12-15 10:03:10,737:DEBUG:letsencrypt.error_handler:Calling registered functions
2015-12-15 10:03:10,742:DEBUG:letsencrypt.cli:Exiting abnormally:
Traceback (most recent call last):
  File "/usr/local/bin/letsencrypt", line 11, in <module>
    sys.exit(main())
  File "~/.local/share/letsencrypt/local/lib/python2.7/site-packages/letsencrypt/cli.py", line 1283, in main
    return args.func(args, config, plugins)
  File "~/.local/share/letsencrypt/local/lib/python2.7/site-packages/letsencrypt/cli.py", line 474, in run
    lineage.chain, lineage.fullchain)
  File "~/.local/share/letsencrypt/local/lib/python2.7/site-packages/letsencrypt/client.py", line 378, in deploy_certificate
    self.installer.save("Deployed Let's Encrypt Certificate")
  File "~/.local/share/letsencrypt/local/lib/python2.7/site-packages/letsencrypt_apache/augeas_configurator.py", line 135, in save
    raise errors.PluginError(str(err))
PluginError: Unable to add title

The command line used is:

letsencrypt --text --rsa-key-size 4096 --email user@domain.tld --agree-tos --renew-by-default --apache --apache-le-vhost-ext .ssl.conf --no-redirect -d <list_of_domains>

Any idea on what’s going on?