Google Vertex AI (generative AI) error
Vertex AI 503 UNAVAILABLE: what it means and how to fix it
503 UNAVAILABLERetry? YesLast verified 1 documented fix2 sources
What it means
The service is temporarily unavailable.
Causes
- The server is not responding to incoming requests
How to fix it
- Fix 1.
The unavailable status might be temporary; retry with exponential backoff. If the error persists, contact support.
More Vertex AI errors
All 11 Vertex AI errors400 INVALID_ARGUMENT / FAILED_PRECONDITIONRetry? No401 UNAUTHENTICATEDRetry? No403 PERMISSION_DENIEDRetry? No404 NOT_FOUNDRetry? No429 RESOURCE_EXHAUSTEDRetry? Yes429 Resource exhausted, please try again laterRetry? Yes429 Too many requests. Exceeded the Provisioned ThroughputRetry? Not stated499 CANCELLEDRetry? Not stated
HTTP 503 at other providers
Compare 503 across providers503 ServiceUnavailableExceptionRetry? YesAmazon Bedrock503 Server ErrorRetry? YesAzure OpenAI503 - Server OverloadedRetry? YesDeepSeek API503 service_unavailableRetry? YesGemini API503 UNAVAILABLERetry? YesGemini API503 Service UnavailableRetry? YesGroq API503 Service unavailableRetry? YesMistral API503 service_unavailable_error server_is_overloadedRetry? YesOpenAI API503 No available model provider meets your routing requirementsRetry? YesOpenRouter503 provider_overloadedRetry? YesOpenRouter
FAQ
What does the Vertex AI error "503 UNAVAILABLE" mean?
The service is temporarily unavailable.
How do I fix Vertex AI "503 UNAVAILABLE"?
The unavailable status might be temporary; retry with exponential backoff. If the error persists, contact support.
Should I retry Vertex AI "503 UNAVAILABLE"?
Yes. The official docs treat this error as retryable.
Which other AI APIs return HTTP 503?
Per their official error docs: Amazon Bedrock (503 ServiceUnavailableException), Azure OpenAI (503 Server Error), DeepSeek API (503 - Server Overloaded), Gemini API (503 service_unavailable; 503 UNAVAILABLE), Groq API (503 Service Unavailable), Mistral API (503 Service unavailable), OpenAI API (503 service_unavailable_error server_is_overloaded), OpenRouter (503 No available model provider meets your routing requirements; 503 provider_overloaded).
Sources
Last verified against 2 sources: Vertex AI's official docs and official SDK repositories.
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