This is an Atlas RTS-specific error message that occurs when a user attempts to post more than 30k changes in a single upload. The upload times out/fails and if we click into the activity ID we see the above error message.
What Causes The Issue?
Atlas can only accept 30,000 placement create/update requests per hour. So if a user uploads 250k items, the system will spoon-feed them to Atlas in 30k/hour increments. However, once the platform makes the request to Atlas via RTS (Razorfish Tracking System previously known as Atlas Management Queue [AMQ]), the platform only keeps looking for returned URL’s for three hours and after this time the upload will time out /fail.
How To Fix The Issue
Split the upload file into smaller chunks and then upload into the platform to generate Atlas specific tracking.