Recently, after upgrading from 2.7.4 to 2.7.5 all my agents' status became unavailable even though when I went down further in the resource tree everything was green. Anyway, I decided to start from scratch and reinstalled server-2.7.5 and upgraded all my agents to 2.7.5. Everything is running smoothly now except for a few things.
Two of my servers' availibility come up as question marks. The inventory process comes up with no new services/servers/etc... Also, when I click on the platform it says my configuration is setup wrong and it can't connect to the server via port 2144, the default port. I deleted the token files and restarted the agents, everything seemed fine. They were able to contact the server via port 2144.
Do the agent logs (located in agent-2.7.5/logs) on either of the unavailable machines show anything of use?
For clarification, when you setup an agent it contacts the server on port 7080 (or 7443 if you have ssl enabled), the server then responds back to the agent on port 2144, so you need to make sure both those communication channels are available.