diff --git a/letsencrypt/cli.py b/letsencrypt/cli.py
index e51490379..88d16be73 100644
--- a/letsencrypt/cli.py
+++ b/letsencrypt/cli.py
@@ -775,7 +775,7 @@ def _restore_plugin_configs(config, renewalparams):
     plugin_prefixes = [renewalparams["authenticator"]]
     if renewalparams.get("installer", None) is not None:
         plugin_prefixes.append(renewalparams["installer"])
-    for plugin_prefix in set(renewalparams):
+    for plugin_prefix in set(plugin_prefixes):
         for config_item, config_value in renewalparams.iteritems():
             if config_item.startswith(plugin_prefix + "_"):
                 # Avoid confusion when, for example, "csr = None" (avoid