401 | Correct API and credential type; token expiry | Authentication. Refreshable clients retry once; static-token clients need a replacement. |
403 | Core token scopes or Platform key scopes | Verify the operation’s scope and selected workspace. |
400 on an event | Integer item/event/context IDs, known item, required user | Events and ID migration. |
| Empty recommendations | Active items, context, filters, seed and seen-item policy | Test a less restrictive request, then use Explainability. |
| One failed rail | That rail’s status and error | Handle partial results in recommendation sets. |
| Repeated catalogue items | Stable metadata.source_item_id and ingestion path | Catalogue. Arbitrary metadata identifiers are not deduplication keys. |
| Rule has no effect | Active state, schedule, context, conditions, segment, Rules stage | Rules Engine. Inclusion in an experiment does not activate an inactive rule. |
| Embed is blank | Allowed origin, publishable key, catalogue display metadata, context | Website embed. Inspect the browser network response. |
| Events disappear at shutdown | Buffered events still pending | Flush while the runtime remains active and observe the individual send results. |
| Analytics is missing or illustrative | Add-on state, retention, Real/Sample data selection, event arrival | Analytics. |
| Training cannot start | Plan, signal template and readiness requirements | Models and Events. |
| Unexpected settings change | Current workspace and recent edits | Activity. |
