Error NewNullResponse Yosemite

Hello I'm having a problem to download any app from the Apple Store.

The error that is that giving is NewNullresponse, I've tried to resolve as follows, but not against the (storeagent).

1) Quit App Store

2) Go to the Activity Monitor (Utilites folder), and search for "store". You need to Force Quit the following:

A) com.apple.appstore.Plugin ... then select Exit, then select Force Quit

B) storeagent then select Exit, then select Force Quit

3) Go to the Terminal (Utilities folder) and enter:

rm ~ /Library/Preferences/com.apple.appstore.plist

press enter

rm ~ /Library/Preferences/com.apple.storeagent.plist

press enter

rm -rf ~ / Library / Preferences / ByHost / *

press enter

4) Open the App Store, you're done!

Does anyone know how to solve?