Try internal authentication URL if external fails.

third_party/upload.py

Index: third_party/upload.py
diff --git a/third_party/upload.py b/third_party/upload.py
index 0aae84c1ea3dcaa8e76fdd71b6c9c0c2dd2709e4..f3100211c216fed08f82d28e73208d19e8f4c140 100755
--- a/third_party/upload.py
+++ b/third_party/upload.py
@@ -289,7 +289,7 @@ class AbstractRpcServer(object):
       req.add_header(key, value)
     return req
 
-  def _GetAuthToken(self, email, password):
+  def _GetAuthToken(self, email, password, internal=False):
     """Uses ClientLogin to authenticate the user, returning an auth token.
 
     Args:
@@ -307,8 +307,9 @@ class AbstractRpcServer(object):
     if self.host.endswith(".google.com"):
       # Needed for use inside Google.
       account_type = "HOSTED"
+    service = ('ClientLogin') if not internal else ('ClientAuth')
     req = self._CreateRequest(
-        url="https://www.google.com/accounts/ClientLogin",
+        url="https://www.google.com/accounts/%s" % (service,),
         data=urllib.urlencode({
             "Email": email,
             "Passwd": password,
@@ -373,9 +374,18 @@ class AbstractRpcServer(object):
     """
     for i in range(3):
       credentials = self.auth_function()
+
+      # Try external, then internal.
+      exc = None
       try:
         auth_token = self._GetAuthToken(credentials[0], credentials[1])
-      except ClientLoginError, e:
+      except urllib2.HTTPError:
+        try:
+          auth_token = self._GetAuthToken(credentials[0], credentials[1],
+                                          internal=True)
+        except ClientLoginError, e:
+          exc = e
+      if exc:
         print >> sys.stderr, ''
         if e.reason == "BadAuthentication":

[Vadim Sh., 2015/04/07 17:31:10]

this things may be different for ClientAuth. Try entering a wrong password to
verify.

           if e.info == "InvalidSecondFactor":
@@ -409,7 +419,7 @@ class AbstractRpcServer(object):
           print >> sys.stderr, "The service is not available; try again later."
         else:
           # Unknown error.
-          raise
+          raise exc
         print >> sys.stderr, ''
         continue
       self._GetAuthCookie(auth_token)