diff --git a/packages/xo-server-transport-email/package.json b/packages/xo-server-transport-email/package.json
index 52c5f3901..0b5a90e85 100644
--- a/packages/xo-server-transport-email/package.json
+++ b/packages/xo-server-transport-email/package.json
@@ -30,7 +30,7 @@
   "dependencies": {
     "nodemailer": "^2.4.2",
     "nodemailer-markdown": "^1.0.0",
-    "promise-toolbox": "^0.5.1"
+    "promise-toolbox": "^0.6.0"
   },
   "devDependencies": {
     "babel-cli": "^6.10.1",
diff --git a/packages/xo-server-transport-email/src/index.js b/packages/xo-server-transport-email/src/index.js
index 4cd34a6d5..fb425abee 100644
--- a/packages/xo-server-transport-email/src/index.js
+++ b/packages/xo-server-transport-email/src/index.js
@@ -130,7 +130,7 @@ class TransportEmailPlugin {
     transport.use('compile', markdownCompiler)
 
     this._conf = conf
-    this._send = transport.sendMail::promisify(transport)
+    this._send = promisify(transport.sendMail, transport)
   }
 
   load () {