Servers crashing - How do you diagnose the issue?

Our beta test server kept crashing today. How are we supposed to know if it’s something we did wrong (script issues etc.), or just Roblox backend crashing on us? Is there any mechanism to get post-mortem information?

We were doing a large beta-test today to check on lag etc…
It ran fine for quite awhile to begin with (45 minutes) and then the server died. People re-joined the new server, but after that, the servers kept crashing more frequently (about 5 minutes).

Is there anything in the Developer Console that we should focus on? Unfortunately, this was a specific day organizing a large group for testing (>30 people) which will be harder to do again without going public.