Error Class Code: 6001 - No Match for argument subscription-manager*

I am trying to migrate my Red Hat Enterprise Linux Server release 6.9 (Santiago) systems from RHN to RHSM. I am using the instructions from https://access.redhat.com/products/red-hat-subscription-management/#migration.

When I do this...

yum search subscription-manager-migration -v

I get this...

There was an error communicating with RHN.
RHN Satellite or RHN Classic support will be disabled.
rhn-plugin: Error communicating with server. The message was:

Error Class Code: 6001

I do not have subscription-manager* on the systems.

Does anyone have the repo settings I need, or other suggestions on how to get past this sticking point in the migration?

Thanks