Phalcon同时执行请求时出现致命错误 - 服务器WAMP

Question

I'm creating an application that on the front end will run a SPA with VueJS and in the back end a webservice with Phalcon. I'm having a problem when I make two asynchronous calls simultaneously to the API (located on my test machine) I receive the following error on the second call:

<br />
<b>Fatal error</b>:  Uncaught Error: Access to undeclared static property: 
Phalcon\Di::$_default in D:\wamp64\www\web-service\public_html\index.php:19
Stack trace:
#0 [internal function]: Phalcon\Di-&gt;__construct()
#1 D:\wamp64\www\web-service\public_html\index.php(19): 
Phalcon\Di\FactoryDefault-&gt;__construct()
#2 {main}

Next Error: Access to undeclared static property: Phalcon\Di::$_default in 
D:\wamp64\www\web-service\public_html\index.php:19
Stack trace:
#0 [internal function]: Phalcon\Di-&gt;__construct()
#1 D:\wamp64\www\web-service\public_html\index.php(19): 
Phalcon\Di\FactoryDefault-&gt;__construct()
#2 {main}
  thrown in <b>D:\wamp64\www\web-service\public_html\index.php</b> on 
line <b>19</b><br />

If I run each call after another, both work correctly.

My server run on a Windows machine with WAMP