An unexpected error has occurred; try refreshing your project again. If the problem persists, please submit this error ID to Adobe Customer Care for further diagnosis: 01236453-da5a-4a67-8a6c-84a3aa454281
If you've been away from AA for a while (e.g. last logged in in the morning, and now you're working on your project in the afternoon), your AA session might have ended already. Try re-opening AA (e.g. from experience.adobe.com), then re-open your project.