Getting oAuth2 token error

[Echo13]

I have an issue when I try to get access token using API https://api.sandbox.paypal.com/v1/oauth2/token 

Now it send me an error though it was working about 10 hours ago.

 { "error": "internal_error", "error_description": "Error communicating to UserRead com.netflix.hystrix.exception.HystrixRuntimeException: userread.POST timed-out and no fallback available." } 

Does anyone have the same issue and how to fix it?

Thanks.