diff --git a/packages/lib/serverConfig.ts b/packages/lib/serverConfig.ts
index 23bf7343dd..3e6d10993e 100644
--- a/packages/lib/serverConfig.ts
+++ b/packages/lib/serverConfig.ts
@@ -10,13 +10,18 @@ function detectTransport(): SendmailTransport.Options | SMTPConnection.Options |
 
   if (process.env.EMAIL_SERVER_HOST) {
     const port = parseInt(process.env.EMAIL_SERVER_PORT || "");
+    const auth =
+      process.env.EMAIL_SERVER_USER && process.env.EMAIL_SERVER_PASSWORD
+        ? {
+            user: process.env.EMAIL_SERVER_USER,
+            pass: process.env.EMAIL_SERVER_PASSWORD,
+          }
+        : undefined;
+
     const transport = {
       host: process.env.EMAIL_SERVER_HOST,
       port,
-      auth: {
-        user: process.env.EMAIL_SERVER_USER,
-        pass: process.env.EMAIL_SERVER_PASSWORD,
-      },
+      auth,
       secure: port === 465,
       tls: {
         rejectUnauthorized: !isENVDev,