This is not a fix, but a workaround for repositories not on HTTPS yet. Use with caution.
[ERROR] (...) Could not transfer artifact no.whatever:whatever-client:pom:3.1 from/to maven-default-http-blocker (http://0.0.0.0/): Blocked mirror for repositories: [releases (http://unportected.com/nexus/content/repositories/releases, defaul)] -> [Help 1]