Hello Sean,
I modified the no workloads.py to add the consoleauth code, so now it does note returns errors during live migration phase, as I wrote in my last email.
Keep in mind my stein is from an upgrade.
Sorry if I am not sending all email history here, but if message body is too big the email needs the moderator approval.
Anycase, I added the following code:

This option has been added as deprecated originally because it is used
for avoiding a upgrade issue and it will not be used in the future.
See the help text for more details.
Enable the consoleauth service to avoid resetting unexpired consoles.

Console token authorizations have moved from the ``nova-consoleauth`` service
to the database, so all new consoles will be supported by the database backend.
With this, consoles that existed before database backend support will be reset.
For most operators, this should be a minimal disruption as the default TTL of a
console token is 10 minutes.

Operators that have much longer token TTL configured or otherwise wish to avoid
immediately resetting all existing consoles can enable this flag to continue
using the ``nova-consoleauth`` service in addition to the database backend.
Once all of the old ``nova-consoleauth`` supported console tokens have expired,
this flag should be disabled. For example, if a deployment has configured a
token TTL of one hour, the operator may disable the flag, one hour after
deploying the new code during an upgrade.

.. note:: Cells v1 was not converted to use the database backend for
  console token authorizations. Cells v1 console token authorizations will
  continue to be supported by the ``nova-consoleauth`` service and use of
  the ``[workarounds]/enable_consoleauth`` option does not apply to
  Cells v1 users.

Related options:

* ``[consoleauth]/token_ttl``

Now the live migration starts e the instance is moved  but the it continues to be unreachable after live migration.
It starts to respond only when it starts a connection (for example a polling to ntp server).
If I disable chrony in the instance, it stop to respond for ever.
Best Regards