title: "We're sorry, a server error occurred." when adding editor without google account
body: <p>When I tried to add a new editor, (only 1) using the following line of code:</p>
  
  <pre><code>myfile.addEditors([emailsAdd[i]]);
  </code></pre>
  
  <p>I got the error message:</p>
  
  <blockquote>
    <p>"We're sorry, a server error occurred. Please wait a bit and try
    again."</p>
  </blockquote>
  
  <p>I tried to add the user manually and I came to know that his email address is not associated with a Google acoount.</p>
  
  <blockquote>
    <p>Are you sure? 
    You are sending an invitation to xy. Since there is no Google account associated with this email address, anyone holding this invitation will have access without signing in."</p>
  </blockquote>
  
  <p>However, yesterday I was able to add an email addresses not associated with Google accounts (same snippet, but using another script and another spreadsheet). Both spreadsheets are new spreadsheets, both spreadsheets' access is set to private. Why does it sometimes work to add new users without GA and sometimes it doesn't? Is there a way to control this behaviour?</p>
  
  <p>Thanks,
  Andreas</p>