I want to know what Stats dropped reason codes mean - outcomes like rate_limited and invalid, and reasons such as project_quota_error_usage_exceeded, project_abuse_limit, and cors (disallowed domain / Allowed Domains).

On Stats, dropped data is grouped by outcome (accepted, filtered, rate_limited, invalid, client_discard) along with a more specific reason. For the full glossary of UI labels, see Stats.

The project has used its spend allocation for that category, and there is no remaining unallocated org quota available for it to use. Events stop being accepted for that project until allocation or shared quota becomes available again.

You can adjust allocations under Settings → Spend Allocations, or increase your reserved / pay-as-you-go volume.

Sentry applied a per-project abuse (internal) rate limit because the project was sending excessive volume. In Stats, this appears as Internal Limit.

These limits are not customer-configurable. Reduce event volume using sampling, inbound filters, beforeSend, or similar controls. If the limit remains in place after your volume drops, contact Sentry Support.

Sentry rejected the request because the Origin or Referer header didn’t match the project’s Allowed Domains list. In Stats, this appears as Disallowed Domain.

This is not a browser CORS failure on your own API. To fix it, add the sending origin to the project’s Allowed Domains.

For step-by-step instructions, see How to handle "event submission rejected with_reason: Cors" errors.