Why should this be of interest:
1. Google asked you ;-)
2. if you want to use Google PageSpeed Tools, to analyze and optimize your website, its mandatory, because PageSpeed just serves the full domain (incl. www.)
This is what happend if you typed www.berlininvestment.com into a browser:
Google asked "To enable this redirect, you must change the A record with your domain host."
I started to dig into the problem at the domain hosting level.
In my case its nicely solved, as my perfect German Hosting Company provides the famous cPanel admin panel.
I couldn't figure it out and called the hosting company.
My site is a wordpress blog self hosted as you could guess.
If this problem occures, then first go to wp-admin panel and check under settings the following:
In the General Settings:
Actually Google tells you to do some works in the CNAME and A-Records of your server.
But in my case it was misleading, and thanks to the best (at least the fasters) hosting company in the world I found the mistake.
Not my CNAME or anything else attached to redirects etc were the problem BUT my wordpress settings.