I've got OEM 12c set up against a few of my Oracle instances and it's been working well, but recently it stopped providing any data under the ASH analytics.
I can still navigate to the page and the server details continue to scroll, but the rest of the page stays blank. I can't get any wait event data, load map or anything in the lower 2/3 of the screen.
I've stopped and restarted the monitor stack with no change. I'm familiar with the DB side of things and there's nothing obvious there, but know very little about the middleware layer.
Can anyone tell me where I should start looking for issues ?