It seems GAIA had changed dosserver rules today, so we can go back to accounts.google.com.

chrome/common/net/gaia/google_service_auth_error.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // A GoogleServiceAuthError is immutable, plain old data representing an
 // error from an attempt to authenticate with a Google service.
 // It could be from Google Accounts itself, or any service using Google
 // Accounts (e.g expired credentials).  It may contain additional data such as
 // captcha or OTP challenges.
 
@@ skipping 37 matching lines @@
     // The GAIA user is not authorized to use the service.
     USER_NOT_SIGNED_UP = 2,
 
     // Could not connect to server to verify credentials. This could be in
     // response to either failure to connect to GAIA or failure to connect to
     // the service needing GAIA tokens during authentication.
     CONNECTION_FAILED = 3,
 
     // The user needs to satisfy a CAPTCHA challenge to unlock their account.
     // If no other information is available, this can be resolved by visiting
-    // https://www.google.com/accounts/DisplayUnlockCaptcha. Otherwise,
-    // captcha() will provide details about the associated challenge.
+    // https://accounts.google.com/DisplayUnlockCaptcha. Otherwise, captcha()
+    // will provide details about the associated challenge.
     CAPTCHA_REQUIRED = 4,
 
     // The user account has been deleted.
     ACCOUNT_DELETED = 5,
 
     // The user account has been disabled.
     ACCOUNT_DISABLED = 6,
 
     // The service is not available; try again later.
     SERVICE_UNAVAILABLE = 7,
@@ skipping 123 matching lines @@
                          const std::string& alternate_text,
                          int field_length);
 
   State state_;
   Captcha captcha_;
   SecondFactor second_factor_;
   int network_error_;
 };
 
 #endif  // CHROME_COMMON_NET_GAIA_GOOGLE_SERVICE_AUTH_ERROR_H_