From 1559 to 1602 UTC on Saturday, May 11, a database migration unexpectedly resulted in the LangSmith API being briefly unavailable.
During this time, any already-submitted runs would have been processed but net-new runs would have been rejected with a 500 error and, by default, not retried by the LangSmith SDK.
This issue is no longer occurring and we are taking long-term measures to prevent a recurrence outside of a scheduled maintenance window.