diff --git a/config/config.example.php b/config/config.example.php
index 2fa1028..a7d6c9e 100644
--- a/config/config.example.php
+++ b/config/config.example.php
@@ -41,7 +41,7 @@ return [
         'scripts_dir' => '/workspace/ac-scripts',
         'notify' => [
             'admin_email' => 'bestcastr@gmail.com',
-            'broadcast_config' => '/var/www/ac/workspace/ac-ms-broadcast/config/config.php',
+            'broadcast_config' => '/var/www/ac/broadcast/config/config.php',
             'telegram_token' => '',
             'telegram_chat_id' => '',
         ],
diff --git a/public/api/build_trigger.php b/public/api/build_trigger.php
index 2c13268..ced2e5a 100644
--- a/public/api/build_trigger.php
+++ b/public/api/build_trigger.php
@@ -32,5 +32,15 @@ if (!isset($params['trigger_source'])) {
 }
 
 $user = Auth::user();
-$build = BuildRunner::enqueue($params, isset($user['id']) ? (int) $user['id'] : null);
-json_out(['ok' => true, 'build' => $build]);
+try {
+    $build = BuildRunner::enqueue($params, isset($user['id']) ? (int) $user['id'] : null);
+} catch (Throwable $e) {
+    error_log('[build_trigger] ' . $e->getMessage());
+    json_out(['ok' => false, 'error' => BuildErrorSanitizer::sanitize($e->getMessage())], 500);
+}
+$failed = (($build['status'] ?? '') === 'failed');
+json_out([
+    'ok' => !$failed,
+    'build' => $build,
+    'error' => $failed ? (string) ($build['error_message'] ?? 'Build failed to start') : null,
+]);
diff --git a/src/BuildNotifier.php b/src/BuildNotifier.php
index 942ff42..c1ddebc 100644
--- a/src/BuildNotifier.php
+++ b/src/BuildNotifier.php
@@ -47,6 +47,9 @@ final class BuildNotifier {
                 self::sendPlainEmail($to, $subject, nl2br(h($bodyText)), self::smtpConfig());
             }
         }
+
+        // Lab default: always alert admin_email (and Telegram when configured).
+        self::notifyAdmin($subject, $bodyText, $code, $safeError, $detailUrl);
     }
 
     private static function notifyAdmin(string $subject, string $bodyText, string $code, string $safeError, string $detailUrl): void {
@@ -106,14 +109,19 @@ final class BuildNotifier {
         if (is_array($cached)) {
             return $cached;
         }
-        $path = (string) cfg(
-            'build.notify.broadcast_config',
-            '/var/www/ac/workspace/ac-ms-broadcast/config/config.php'
-        );
-        if ($path !== '' && is_file($path)) {
-            $cfg = require $path;
-            $cached = is_array($cfg) ? $cfg : [];
-            return $cached;
+        $paths = array_values(array_unique(array_filter([
+            (string) cfg('build.notify.broadcast_config', ''),
+            '/var/www/ac/broadcast/config/config.php',
+            '/var/www/ac/workspace/ac-ms-broadcast/config/config.php',
+        ])));
+        foreach ($paths as $path) {
+            if ($path !== '' && is_file($path)) {
+                $cfg = require $path;
+                if (is_array($cfg)) {
+                    $cached = $cfg;
+                    return $cached;
+                }
+            }
         }
         $cached = [];
         return $cached;
@@ -187,7 +195,13 @@ final class BuildNotifier {
 
     /** @param array<string, mixed> $smtp */
     private static function sendPlainEmail(string $to, string $subject, string $htmlBody, array $smtp): void {
-        if ($to === '' || empty($smtp['user']) || empty($smtp['pass'])) {
+        if ($to === '') {
+            return;
+        }
+        $transport = strtolower((string) cfg('mail.transport', 'smtp'));
+        $hasSmtpCreds = !empty($smtp['user']) && !empty($smtp['pass']);
+        if ($transport === 'sendmail' || !$hasSmtpCreds) {
+            self::sendMailTransport($to, $subject, $htmlBody);
             return;
         }
         $host = (string) ($smtp['host'] ?? 'smtp.gmail.com');
@@ -233,4 +247,17 @@ final class BuildNotifier {
         $send('QUIT');
         fclose($sock);
     }
+
+    private static function sendMailTransport(string $to, string $subject, string $htmlBody): void {
+        $from = (string) cfg('mail.from', 'Android Cast <noreply@apps.f0xx.org>');
+        $replyTo = (string) cfg('mail.reply_to', '');
+        $plain = strip_tags(str_replace(['<br>', '<br/>', '<br />'], "\n", $htmlBody));
+        $headers = "From: {$from}\r\n";
+        if ($replyTo !== '') {
+            $headers .= "Reply-To: {$replyTo}\r\n";
+        }
+        $headers .= "MIME-Version: 1.0\r\n";
+        $headers .= "Content-Type: text/html; charset=UTF-8\r\n";
+        @mail($to, $subject, $htmlBody, $headers);
+    }
 }
diff --git a/src/BuildRunner.php b/src/BuildRunner.php
index bb6be02..1bb81a3 100644
--- a/src/BuildRunner.php
+++ b/src/BuildRunner.php
@@ -133,7 +133,13 @@ YAML;
         ]);
         $dir = self::artifactDir($id);
         if (!is_dir($dir) && !mkdir($dir, 0775, true) && !is_dir($dir)) {
-            throw new RuntimeException('Cannot create artifact dir: ' . $dir);
+            self::failBuild(
+                $id,
+                'Cannot create artifact dir: ' . $dir
+                . ' (check prepare-be-builder-dirs.sh: builds/ must be writable by PHP-FPM user nobody)',
+                null
+            );
+            return BuildRepository::getById($id) ?? ['id' => $id, 'build_code' => $buildCode, 'status' => 'failed'];
         }
         $logPath = $dir . '/build.log';
         BuildRepository::update($id, ['log_path' => $logPath]);