What Are the Possible Causes If the Message "Backend unavailable" or "Backend timeout" Is Displayed?
The following table lists the possible causes if a backend service fails to be invoked or the invocation times out.
Possible Cause |
Solution |
|---|---|
The backend service address is incorrect. |
Change the backend service address in the API definition. If the domain name is used, ensure that the domain name can be correctly resolved to the IP address of the backend service. |
The timeout duration is incorrect. If a backend service fails to return a response within the configured timeout duration, APIG displays a message indicating that the backend service fails to be invoked. |
Increase the backend timeout duration in the API definition. |
If the backend address is an ECS address, the security group to which the ECS belongs may block the request in the inbound or outbound direction. |
Check the security group to which the ECS belongs and ensure that the inbound and outbound port rules and protocols of this security group are correct. |
The request protocol is incorrect. For example, the backend service uses HTTP, but HTTPS is selected on APIG. |
Ensure that the protocol of the created API is the same as that of the backend service. |
The backend service URL is unreachable. |
Check the URL. |
API Calling FAQs
- What Are the Possible Causes for an API Calling Failure?
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- Why Am I Seeing the Error Message "414 Request URI too large" When I Call an API?
- What Should I Do If "The API does not exist or has not been published in the environment." Is Displayed?
- Why Am I Seeing the Message "No backend available"?
- What Are the Possible Causes If the Message "Backend unavailable" or "Backend timeout" Is Displayed?
- Why Am I Seeing the Message "Backend domain name resolution failed" When a Backend Service Is Called?
- Why Doesn't Modification of the backend_timeout Parameter Take Effect?
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- App (Credential) FAQs
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- Does APIG Support WebSocket Data Transmission?
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- How Will the Requests for an API with Multiple Backend Policies Be Matched and Executed?
- Is There a Limit on the Size of the Response to an API Request?
- How Can I Access Backend Services over Public Networks Through APIG?
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