AWS Lambda Function URL error (failed)net::ERR_NAME_NOT_RESOLVED

The net::ERR_NAME_NOT_RESOLVED error indicates that the DNS resolution for your AWS Lambda function URL failed. This can happen due to various reasons, especially when using mobile data. Here are some steps to troubleshoot and potentially resolve the issue:

1. Check DNS Settings on Mobile Data:

• Mobile Carrier DNS: Some mobile carriers might use DNS resolvers that do not properly resolve AWS endpoints. You can try changing the DNS settings on your mobile device to use a public DNS resolver like Google DNS (8.8.8.8, 8.8.4.4) or Cloudflare DNS (1.1.1.1).
• Device Settings: Ensure that your device's DNS settings are correctly configured. Sometimes, flushing the DNS cache on your device might help.

2. Verify Lambda Function URL:

• Correct URL: Double-check that you are using the correct Lambda function URL. Ensure there are no typos or errors in the URL.
• URL Format: The URL should be in the format https://<function-url-id>.lambda-url.<region>.on.aws.

3. Check Lambda Function Configuration:

• Function URL Status: Ensure that the function URL is properly configured and enabled in the AWS Management Console.
• Permissions: Make sure that the function URL has the correct permissions to be accessed. This includes ensuring that the function URL is publicly accessible if required.

4. Use Different Network:

• Network Comparison: Try accessing the Lambda function URL from a different network, such as Wi-Fi, to see if the issue persists. This can help determine if the problem is specific to mobile data.

5. Check for AWS Outages:

• AWS Service Status: Sometimes, AWS services might experience regional outages or DNS issues. Check the AWS Service Health Dashboard for any ongoing issues: AWS Service Health Dashboard.

6. Use Alternative Tools:

• DNS Resolution Tools: Use tools like nslookup or dig to manually check if the Lambda function URL resolves correctly.

nslookup <function-url>
dig <function-url>

Example of Changing DNS Settings on Mobile Device:

Android:

• Go to Settings.
• Tap on Network & Internet.
• Tap on Advanced.
• Tap on Private DNS.
• Select Private DNS provider hostname and enter dns.google for Google DNS or 1dot1dot1dot1.cloudflare-dns.com for Cloudflare DNS.

iOS:

• Go to Settings.
• Tap on Wi-Fi.
• Tap the i icon next to your connected Wi-Fi network.
• Tap on Configure DNS.
• Select Manual.
• Add 8.8.8.8 and 8.8.4.4 for Google DNS, or 1.1.1.1 and 1.0.0.1 for Cloudflare DNS.

Example of Using dig:

dig <function-url>

Example of Using nslookup:

nslookup <function-url>

By following these steps, you should be able to identify whether the issue is with DNS resolution on your mobile network or with the AWS Lambda function URL configuration.