title: Could not resolve com.android.support:appcompat-v7:26.1.0
body: <p>After upgrading to androidstudio 3.0 gradle stopped working:</p>
  
  <p>Unable to resolve dependency for ':app@debug/compileClasspath': Could not resolve com.android.support:appcompat-v7:26.1.0.</p>
  
  <p>Could not resolve com.android.support:appcompat-v7:26.1.0.
  Required by:
      project :app</p>
  
  <blockquote>
    <p>Could not resolve com.android.support:appcompat-v7:26.1.0.
    Could not get resource '<a href="https://dl.google.com/dl/android/maven2/com/android/support/appcompat-v7/26.1.0/appcompat-v7-26.1.0.pom" rel="noreferrer">https://dl.google.com/dl/android/maven2/com/android/support/appcompat-v7/26.1.0/appcompat-v7-26.1.0.pom</a>'.
    Could not GET '<a href="https://dl.google.com/dl/android/maven2/com/android/support/appcompat-v7/26.1.0/appcompat-v7-26.1.0.pom" rel="noreferrer">https://dl.google.com/dl/android/maven2/com/android/support/appcompat-v7/26.1.0/appcompat-v7-26.1.0.pom</a>'.
    Connect to dl.google.com:443 [dl.google.com/172.217.22.110] failed: Connection timed out: connect
    Connection timed out: connect</p>
  </blockquote>
  
  <p>I have checked the proxy and it works.</p>
  
  <p>This is a new project, nothing was changed from what the android studio wizard generates.</p>
  
  <p>Thanks for your help. </p>