I’m having the same problem (NEGOTIATE authentication error: No valid credentials provided (Mechanism level: No valid credentials provided)) with Gradle 1.4 and 1.5.
I’m behind a proxy and using these settings:
systemProp.http.proxyHost=proxy.company.com
systemProp.http.proxyPort=8080
systemProp.http.proxyUser=user
systemProp.http.proxyPassword=password
systemProp.http.nonProxyHosts=localhost
http.auth.ntlm.domain=DOMAIN
systemProp.http.keepAlive=true
The same exact configuration works with Gradle 1.3.
With 1.3 I also get the error message, but only once!
When I switch to 1.4 or 1.5 it gets stuck repeating the authentication error again and again.
Output: Gist