fix for #691

api.php

                 $response = $this->responder->error(ErrorCode::ORIGIN_FORBIDDEN, $origin);
             } elseif ($method == 'OPTIONS') {
                 $response = ResponseFactory::fromStatus(ResponseFactory::OK);
-                $allowHeaders = $this->getProperty('allowHeaders', 'Content-Type, X-XSRF-TOKEN, X-Authorization');
+                $allowHeaders = $this->getProperty('allowHeaders', 'Content-Type, X-XSRF-TOKEN, X-Authorization, X-Debug-Info, X-Exception-Name, X-Exception-Message, X-Exception-File');
                 if ($allowHeaders) {
                     $response = $response->withHeader('Access-Control-Allow-Headers', $allowHeaders);
                 }
                 if ($maxAge) {
                     $response = $response->withHeader('Access-Control-Max-Age', $maxAge);
                 }
-                $exposeHeaders = $this->getProperty('exposeHeaders', '');
+                $exposeHeaders = $this->getProperty('exposeHeaders', 'X-Debug-Info, X-Exception-Name, X-Exception-Message, X-Exception-File');
                 if ($exposeHeaders) {
                     $response = $response->withHeader('Access-Control-Expose-Headers', $exposeHeaders);
                 }