When I try to use SBT some files cannot be downloaded with the following error:

> 
> Server access Error: sun.security.validator.ValidatorException: PKIX
>  path building failed:
>  sun.security.provider.certpath.SunCertPathBuilderException: unable to
>  find valid certification path to requested target
>  url=<https://repo1.maven.org/maven2/org/scala-sbt/sbt/1.0.0-M4/sbt-1.0.0-M4.jar>
> 
> 
> 

I have followed some advice on Stack Overflow and imported the corporate proxy SSL certificate with the java keytool as described in:
[SSL certificate problem in a web service proxy](https://stackoverflow.com/questions/6492122/ssl-certificate-problem-in-a-web-service-proxy)

It does not seems to affect the SBT tool. Does it look in a different keystore? Any ideas?

If I paste the URL on the browser the file downloads.

I get this error when simply running the SBT tool I have installed. When I try to create a SBT project on IntelliJ Idea and update it, it gives me the same error with different URLs. Same thing when trying to use the lightbend activator.