diff --git a/src/Mail.ts b/src/Mail.ts
index 377ad92..e412617 100644
--- a/src/Mail.ts
+++ b/src/Mail.ts
@@ -20,7 +20,7 @@ export default class Mail {
         const transporter = nodemailer.createTransport({
             host: config.get('mail.host'),
             port: config.get('mail.port'),
-            secure: config.get('mail.secure'),
+            requireTLS: config.get('mail.secure'), // STARTTLS
             auth: {
                 user: config.get('mail.username'),
                 pass: config.get('mail.password'),
diff --git a/src/components/MailComponent.ts b/src/components/MailComponent.ts
index 38fd8b4..18d8998 100644
--- a/src/components/MailComponent.ts
+++ b/src/components/MailComponent.ts
@@ -8,11 +8,11 @@ export default class MailComponent extends ApplicationComponent<void> {
 
 
     public async checkSecuritySettings(): Promise<void> {
-        // if (!config.get<boolean>('mail.secure')) {
-        //     throw new SecurityError('Cannot set mail.secure to false');
-        // }
+        if (!config.get<boolean>('mail.secure')) {
+            throw new SecurityError('Cannot set mail.secure (starttls) to false');
+        }
         if (config.get<boolean>('mail.allow_invalid_tls')) {
-            throw new SecurityError('Cannot set mail.allow_invalid_tls to true');
+            throw new SecurityError('Cannot set mail.allow_invalid_tls (ignore tls failure) to true');
         }
     }