Unable to get local issuer certificate.

[OfekDayan]

Hi,
I'm using this code:

 BinaCPP_websocket::init();
 BinaCPP_websocket::connect_endpoint(ws_depth_onData ,"/ws/!bookTicker"); 
 BinaCPP_websocket::enter_event_loop(); 

That's the error I get:
[2021/05/14 22:28:31:3827] N: LWS: 4.1.6-, loglevel 7
[2021/05/14 22:28:31:3838] N: NET CLI SRV H1 H2 WS IPV6-on
[2021/05/14 22:28:32:0550] E: SSL error: unable to get local issuer certificate (preverify_ok=0;err=20;depth=1)

Any ideas why?