Android Gradle build issue - peer not authenticated (HTTPS)

I’m on Mac El Capitan with Java 1.8.0_65, V-play 2.9

I have a weird problem that occurred from nowhere. When I try to build one of my projects I get this error saying:

FAILURE: Build failed with an exception.

* What went wrong:
A problem occurred configuring root project 'android-build'.
> Could not resolve all dependencies for configuration ':_debugCompile'.
   > Could not resolve net.vplay.plugins:plugin-flurry:2.+.
     Required by:
         :android-build:unspecified
      > Failed to list versions for net.vplay.plugins:plugin-flurry.
         > Unable to load Maven meta-data from https://sdk.felgo.com/maven/net/vplay/plugins/plugin-flurry/maven-metadata.xml.
            > Could not GET 'https://sdk.felgo.com/maven/net/vplay/plugins/plugin-flurry/maven-metadata.xml'.
               > peer not authenticated
   > Could not resolve net.vplay.plugins:plugin-onesignal:2.+.
     Required by:
         :android-build:unspecified
      > Failed to list versions for net.vplay.plugins:plugin-onesignal.
         > Unable to load Maven meta-data from https://sdk.felgo.com/maven/net/vplay/plugins/plugin-onesignal/maven-metadata.xml.
            > Could not GET 'https://sdk.felgo.com/maven/net/vplay/plugins/plugin-onesignal/maven-metadata.xml'.
               > peer not authenticated

Usually when that sort of things happen I add the Root CA of the problematic certificate to cacerts. But this time the Root CA (GlobalSign Root CA) is already in the store. I would be happy to hear any suggestions.

Cheers.