If you are struggling to get Play Framework up and running and you are behind a proxy server here is the solution.
Go to your Play directory (in my case was: /home/andrealmar/softwares/play)
Create the file activatorconfig.txt in ~/.activator/ directory
Put the configs below inside your activatorconfig.txt
# This are the proxy settings we use for activator
# Multiple proxy hosts can be used by separating them with a '|' sign
# Do not enclose the proxy host(s) in quotes
-Dhttp.proxyHost=<strong>188.8.131.52 - your proxy IP/host</strong>
-Dhttp.proxyPort=<strong>82 - your proxy PORT</strong>
-Dhttps.proxyHost=<strong>184.108.40.206 - your proxy IP/host</strong>
-Dhttps.proxyPort=<strong>82 - your proxy PORT</strong>
# Here we configure the hosts which should not go through the proxy. You should include your private network, if applicable.
# These are commented out, but if you need to use authentication for your proxy, please fill these out.
-Dhttp.proxyUser=<strong>your network/proxy user</strong>
-Dhttp.proxyPassword=<strong>your network/proxy password</strong>
And that’s it. Now you can use the activator run command and it will pass through your proxy without any problems.