EFront API not responding (cURL)

I want to test the API and request the all users. My code is the following:

curl -X "GET" ^
"https://virtserver.swaggerhub.com/Epignosis/Efront-API/1.0.0/Users" ^
-H "accept: application/json" ^
-H "Authorization: Basic myToken"

and i don't know why the API is not responding.