Spacewalk successfully registered to RHSM with the help of migration scripts. However, I have an issue while running the activation command:

rhn-satellite-activate -vvv --rhn-cert=Satellite-57.cert

I see the following error;
ERROR: RHN Cert (/root/Satellite-57.cert) does not exist

Am i suppose to get "Satellite-57.cert" automatically while running migration script ? I am not sure where is the certificate for the activation. I can't download it from the Web UI since we have Satellite 6.1.8 registered already, not the Spacewalk.