Affectiva SDK Android Studio affdex not compiling

I have included the maven statement in my project build.gradle and the compile('com.affectiva.android:affdexsdk:3.+') statement in module build.gradle. However I receive the following error

Could not find any matches for com.affectiva.android:affdexsdk:3.+ as no versions of com.affectiva.android:affdexsdk are available.

Additionally the url that I include in maven is: http://maven.affectiva.com/

However, when I visit that url manually I see this: Online Error Message