If the local SSH host keys on an agent are changed then vsmagent needs to be restarted for it to notice those changes. Until then it will continue to report the old ones to connecting clients, which can prevent those clients from connecting if those keys are no longer actually used.
When this happens users will get the prompt:
> WARNING - SECURITY BREACH
> The host key received from the server for the agent you are
> about to connect to and the host key reported by the agent
> itself doesn't concur.
> This almost certainly means there are a third party trying to listen
> to the communication between you and the server
> Contact your systems administrator about this problem!
> You will not be connected to the system at this time
There is no way to bypass this so the sysadmin will need to restart the vsmagent service to get things running again.