fix: add option to disable STARTTLS for SMTP servers without TLS support

Fixes #6018 - adds a 'Disable STARTTLS' checkbox that lets users connect to legacy SMTP servers that don't support encryption

server/notification-providers/smtp.js

@@ -14,11 +14,25 @@ class SMTP extends NotificationProvider {
             host: notification.smtpHost,
             port: notification.smtpPort,
             secure: notification.smtpSecure,
-            tls: {
-                rejectUnauthorized: !notification.smtpIgnoreTLSError || false,
-            },
         };
 
+        // Handle TLS/STARTTLS options
+        if (notification.smtpSecure) {
+            // SMTPS (implicit TLS on port 465)
+            config.tls = {
+                rejectUnauthorized: !notification.smtpIgnoreTLSError || false,
+            };
+        } else if (notification.smtpIgnoreSTARTTLS) {
+            // Disable STARTTLS completely for servers that don't support it
+            // Connection will remain unencrypted
+            config.ignoreTLS = true;
+        } else {
+            // Allow STARTTLS (default behavior for ports 25, 587)
+            config.tls = {
+                rejectUnauthorized: !notification.smtpIgnoreTLSError || false,
+            };
+        }
+
         // Fix #1129
         if (notification.smtpDkimDomain) {
             config.dkim = {

src/components/notifications/SMTP.vue

@@ -56,6 +56,24 @@
             </div>
         </div>
 
+        <div v-if="!$parent.notification.smtpSecure" class="mb-3">
+            <div class="form-check">
+                <input
+                    id="ignore-starttls"
+                    v-model="$parent.notification.smtpIgnoreSTARTTLS"
+                    class="form-check-input"
+                    type="checkbox"
+                    value=""
+                />
+                <label class="form-check-label" for="ignore-starttls">
+                    {{ $t("Disable STARTTLS") }}
+                </label>
+            </div>
+            <div class="form-text">
+                {{ $t("disableSTARTTLSDescription") }}
+            </div>
+        </div>
+
         <div class="mb-3">
             <label for="username" class="form-label">{{ $t("Username") }}</label>
             <input

src/lang/en.json

@@ -585,6 +585,8 @@
     "secureOptionNone": "None / STARTTLS (25, 587)",
     "secureOptionTLS": "TLS (465)",
     "Ignore TLS Error": "Ignore TLS Error",
+    "Disable STARTTLS": "Disable STARTTLS",
+    "disableSTARTTLSDescription": "Enable this option for SMTP servers that do not support STARTTLS. This will send emails over an unencrypted connection.",
     "From Email": "From Email",
     "emailCustomisableContent": "Customisable content",
     "smtpLiquidIntroduction": "The following two fields are templatable via the Liquid templating Language. Please refer to the {0} for usage instructions. These are the available variables:",