Guardrail check failed during agent build

While building the agent, I tested the guardrail feature and encountered a blow error.

error:
Failed at pre-execution guardrail check
detail:
Sending event failed ErrorCode:Agent.BaseError TraceId:7756b96aa4574f8cbd7a3fcfffb71cce Name or service not known

Why did this error occur, and which name or service is not known?