How to implement a failover mechanism by connecting the Solace HA through a single URL

If by “apply for support” you mean contact/use Solace’s Support personnel, you can purchase various support plans. They’re documented here: https://solace.com/support/ I’m not sure of the costs though. But you can even get support on the Standard edition (e.g. free) broker… we have quite a few customers running the free Standard broker in production (vs. Enterprise $$) and only paying us for Support.