Command failed with error 286 (ChangeStreamHistoryLost) / error 280 (ChangeStreamFatalError): resume point was not found in the oplog

Root cause

The resume token is no longer usable, for example because its change history is outside the oplog window. Determine the actual history window and topology; no universal Atlas retention duration applies.

How to fix

1. Inspect the oplog/change-stream history window and size it against measured change volume and recovery needs.
2. Review connector heartbeat and offset flushing behavior for low-activity collections.
3. Use the documented connector recovery/snapshot procedure and reconcile downstream state. Do not manually overwrite the shared Connect offsets topic.