Getmail OAUTH gmail failure

Getmail has been happily pulling stuff down from gmail using OAUTH for, oh,
a week or so, and it's just started doing this:

External password program "/opt/local/bin/getmail-gmail-xoauth-tokens"
wrote to stderr: Traceback (most recent call last):
  File "/opt/local/bin/getmail-gmail-xoauth-tokens", line 115, in <module>
    sys.stdout.write("%s" % auth.token())
  File "/opt/local/bin/getmail-gmail-xoauth-tokens", line 93, in token
    self.refresh_tokens()
  File "/opt/local/bin/getmail-gmail-xoauth-tokens", line 89, in
refresh_tokens
    self.update_config(d)
  File "/opt/local/bin/getmail-gmail-xoauth-tokens", line 65, in
update_config
    self.data['access_token'] = d['access_token']
KeyError: 'access_token'GMAILACCOUNT-rc: operation error (External password
program error (exited 1))

Is it google being google, or have I forgotten to do something important??

From the rc file:
password_command = ("/opt/local/bin/getmail-gmail-xoauth-tokens",
"/home/USERNAME/.getmail/GMAILACCOUNT.json")

I really, really, really haven't changed anything since I got OAUTH
working.  :-)

        Cheers,
                Gary    B-)