title: Google App Script - Unexplained runtime error
body: <p>I'm writing a Gmail extension with Google Apps Script. The extension uses the <code>DriveApp</code> class to save email attachments as Drive files.<br>
  The app worked just fine for the last few weeks. Yesterday, the following exception appeared:<br><br>
  <code>Exception: We're sorry, a server error occurred. Please wait a bit and try again. [line: 10, function: getSubfolderByPath, file: FileMover]</code><br>
  Line 10 is: <code>let curFolder = DriveApp.getFolderById(folderId);</code><br><br>
  The <code>folderId</code> variable is set correctly, I logged it and checked that the directory actually exists.
  I googled this obscure exception, and the only relevant info I found states that this might actually be an internal Google Drive problem, and that it might be related to some ongoing issue with the service. The app doesn't work for more then 24 hours, and I didn't find any notifications about ongoing issues.</p>