Wio Terminal to connect to a hidden SSID

Hi seniors, I m using Wio Terminal to develop an IOT project going to be used inside a semiconductor fab. But I am not struggling again a Wifi connection problem right now.
Inside the fab, what i m trying to do is to connect to a hidden SSID and it don’t need password .
In my code, all I use are the below related Header Files
#include <rpcWiFi.h>
#include <WiFiClient.h>
#include <WebServer.h>

Then I use WiFi.begin(ssid, NULL) to initial a connect to the SSID ( already assgined correct SSID name to the valuable ssid). But just can not get reach to the hidden SSID at all ( as can be check from our fab’s network checking page , no trying is found to attempt to connect to the host )

Hope get your hands , thanks!

Hi, is anybody know solution(s)? thanks for your suggestions.
If currently do not support connect to hidden wifi network, then Wio Terminal is not suitable for my target project.
I do suffering from trouble shooting this issue recently !