Error in SerpAPI workflow (Agent Failing) and Also No clarity why in failing

n8n :

file :

SerpAPI key : 67cd6b0c28aaa78a590394c7f5215c5574341fed4fe550c775f5b59e0471c860
OpenRouter :
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

Payload:
{ "prompt": "Who is Mathesh Natarajan?" }