diff --git a/setup/mail-dovecot.sh b/setup/mail-dovecot.sh
index 4bcc53aa..d1c0516c 100755
--- a/setup/mail-dovecot.sh
+++ b/setup/mail-dovecot.sh
@@ -135,6 +135,14 @@ service lmtp {
   }
 }
 
+# Enable imap-login on localhost to allow the user_external plugin
+# for Nextcloud to do imap authentication. (See #1577)
+service imap-login {
+  inet_listener imap {
+    address = 127.0.0.1
+    port = 143
+  }
+}
 protocol imap {
   mail_max_userip_connections = 20
 }
diff --git a/setup/nextcloud.sh b/setup/nextcloud.sh
index 0783f551..ccae960b 100755
--- a/setup/nextcloud.sh
+++ b/setup/nextcloud.sh
@@ -155,7 +155,7 @@ if [ ! -f $STORAGE_ROOT/owncloud/owncloud.db ]; then
     array(
       'class' => 'OC_User_IMAP',
         'arguments' => array(
-          '${PRIMARY_HOSTNAME}', 993, 'ssl', ''
+          '127.0.0.1', 143, '', ''
          ),
     ),
   ),
@@ -229,7 +229,7 @@ include("$STORAGE_ROOT/owncloud/config.php");
 
 \$CONFIG['mail_domain'] = '$PRIMARY_HOSTNAME';
 
-\$CONFIG['user_backends'] = array(array('class' => 'OC_User_IMAP','arguments' => array('${PRIMARY_HOSTNAME}', 993, 'ssl', ''),),);
+\$CONFIG['user_backends'] = array(array('class' => 'OC_User_IMAP','arguments' => array('127.0.0.1', 143, '', ''),),);
 
 echo "<?php\n\\\$CONFIG = ";
 var_export(\$CONFIG);