title: AMP refferer from subdomain domain.cdn.ampproject.org
body: <p>Since the 27th of january I get according to analytics referrer from<br>
  <a href="http://www-usa--reisetipps-net.cdn.ampproject.org/v/www.usa-reisetipps.net/" rel="nofollow noreferrer">http://www-usa--reisetipps-net.cdn.ampproject.org/v/www.usa-reisetipps.net/</a>...  </p>
  
  <p>Before that they came normally from <a href="http://cdn.ampproject.org/v/www.usa-reisetipps.net/" rel="nofollow noreferrer">http://cdn.ampproject.org/v/www.usa-reisetipps.net/</a>...<br>
  The new Refferer can not be opened.
  Does anyone know the background of the change?</p>