diff --git a/views/admin/horario/calendar.php b/views/admin/horario/calendar.php
index a064a35..40feed0 100644
--- a/views/admin/horario/calendar.php
+++ b/views/admin/horario/calendar.php
@@ -56,7 +56,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST' && in_array($_POST['action'] ?? '', ['
                 if ($id < 0 || !array_key_exists($dia, $dias)) $fail(422, 'Dados inválidos');
                 if (!preg_match($hhmm, $hi) || !preg_match($hhmm, $hf)) $fail(422, 'Horas inválidas');
                 if ($hf <= $hi) $fail(422, 'A hora de fim deve ser depois do início');
-                if (mb_strlen($local) > 50) $fail(422, 'Sala inválida');
+                if (!array_key_exists($local, $salas)) $fail(422, 'Sala inválida');  // enum membership
                 if ($mod < 1 || !db_modalidades_get($pdo, $mod)) $fail(422, 'Modalidade inválida');
                 $payload = [
                     'id_modalidade' => $mod,
@@ -71,8 +71,16 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST' && in_array($_POST['action'] ?? '', ['
                 break;
         }
     } catch (Throwable $e) {
+        // Surface the real cause: log it (same sink as the global handler) so a
+        // failed save on prod is diagnosable, and echo the detail back in dev.
+        if (function_exists('_error_log_write')) {
+            _error_log_write(get_class($e), $e->getMessage(), $e->getFile(), $e->getLine(), $e->getTraceAsString());
+        } else {
+            error_log('[horario/calendar save] ' . $e->getMessage());
+        }
         http_response_code(500);
-        echo json_encode(['ok' => false, 'error' => 'Erro ao guardar']);
+        $detail = (defined('APP_ENV') && APP_ENV === 'prod') ? 'Erro ao guardar' : $e->getMessage();
+        echo json_encode(['ok' => false, 'error' => $detail]);
     }
     exit;
 }