diff --git a/api/src/Mail/Script.php b/api/src/Mail/Script.php
index 787138c4c6..af4ef589cc 100644
--- a/api/src/Mail/Script.php
+++ b/api/src/Mail/Script.php
@@ -607,7 +607,12 @@ class Script
 		//error_log(__METHOD__.__LINE__.array2string($newscript));
 		//print "<pre>$newscript</pre>"; exit;
 		//print "<hr><pre>".htmlentities($newscript)."</pre><hr>";
+
 		try {
+			if (!$connection->hasSpace($this->name, mb_strlen($newscript)))
+			{
+				throw new \Exception(lang("There is no space left to store sieve script, please check sieve_maxscriptsize option on your mailserver's config."));
+			}
 			$connection->installScript($this->name, $newscript, true);
 		}
 		catch (\Exception $e) {
diff --git a/mail/inc/class.mail_sieve.inc.php b/mail/inc/class.mail_sieve.inc.php
index d85be88d30..dcc91fe8fc 100644
--- a/mail/inc/class.mail_sieve.inc.php
+++ b/mail/inc/class.mail_sieve.inc.php
@@ -963,7 +963,7 @@ class mail_sieve
 
 		if($result)
 		{
-			$response->error($result);
+			$response->message($result);
 			return;
 		}
 		$this->saveSessionData();
@@ -1170,7 +1170,7 @@ class mail_sieve
 	{
 		if (!$this->account->imapServer()->setRules($this->rules))
 		{
-			return "update failed";
+			return $this->account->imapServer()->error;
 		}
 	}