Clearspace unreachable error

Running Openfire with Clearspace 2.5.4. One of the admins (set as a system admin) currently gets the below error when they try and login to the Admin console of Openfire:

Clearspace unreachable: make sure Clearspace is up and running or click the login button again to change Openfire configuration.

I’ve tested it with my account and had another admin check it out and were able to login to the admin console fine.

Any thoughts on what might be causing this?