I want to know why Sentry returns 200 OK (or my SDK shows an event ID) but the error does not appear in the UI.

A 200 OK response only confirms that Sentry received the request. It does not guarantee that the event was stored or that it will appear in the Sentry UI. Similarly, an event ID returned by the SDK does not confirm that the event was accepted and stored.

If an event is missing, first check whether it was dropped after ingestion. Go to Stats → Usage, filter by the relevant project, and look for Filtered, Rate Limited, or other dropped-event categories.

You should also check Project Settings → Inbound Filters to make sure a filter, such as one for browser extensions or localhost, isn't preventing the event from being stored.

If Stats doesn't explain why the event was dropped, contact Sentry Support for further help.

For more information about cases where you have an event ID but can't find the event in Sentry, see Why is my event missing in Sentry even though I have an event ID?