Yeah, I’m unfortunately still seeing the same issue on 25.10-RC.1.
It seems like the health check is badly broken. The issue is that it sometimes doesn’t find the credentials file, which middleware should create in the health check just before that. Underlying exception is: “Credentials cache does not exist”.
I needed to add custom code to print the underlying exceptions, since they’re never even logged anywhere and replaced with a generic “Stored machine account secret is invalid” message, which is only half-true…
Since a failing health check now also causes the AD user/group cache to clear (or at least not show) in the frontend, I’ve had custom code on BETA.1 to basically just disable the health check. Everything seemed to work fine then.
I’ll likely just implement the same on RC.1 again, since AD is spammy and unusable without that when editing permissions in the TN UI.
There are more details on the underlying exceptions (that are not logged without custom code) in my comment on JIRA here. (might need to scroll down manually and open all answers to A. Walker)