After moving to the FedRAMP instance of Rally, users in the subscription are no longer able to log into the support site.
This can be caused if you deactivate your commercial SSO partnership that was in place with Broadcom.
In order to be able to access the support site, you will need to maintain an SSO partnership with the commercial Broadcom side in order to access these applications.
In essence, you will need two partnerships with Broadcom; one for FedRAMP and another for the support site.