frontend error and internal server errro message

Based on your logs, you're encountering an "Internal server error" when trying to process audio chunks through your Lambda functions. This is happening after your React Native frontend successfully connects to the WebSocket and sends audio chunks.

The issue appears to be in your Lambda function chain. Here are some potential causes and solutions:

1. Binary data handling: API Gateway WebSocket APIs don't support binary frames directly. Since you're sending base64-encoded audio chunks (as shown in your logs with "base64 preview"), make sure your Lambda functions are properly decoding these. The error might occur if there's an issue with the base64 decoding process.

2. Lambda response format: Your third Lambda function might be returning an improperly formatted response. Ensure it's returning data in the correct format expected by your WebSocket API.

3. Transcription service issues: If you're using Amazon Transcribe with GPT-4o mini, verify that:

• You're using a supported AWS region for Transcribe
• The audio format is compatible (16-bit PCM is typically expected)
• The sample rate is appropriate (commonly 16000 Hz)

4. Error handling: Implement better error handling in your Lambda functions to get more specific error messages rather than the generic "Internal server error".

5. CloudWatch logs: Check the CloudWatch logs for all three Lambda functions to identify where exactly the error is occurring. The logs should provide more detailed information about what's failing.

6. Audio chunk size: Consider adjusting the size of your audio chunks if they're too small or too large.

For your text-to-speech conversion in the third Lambda, make sure you're properly encoding the response for transmission through the WebSocket back to your React Native frontend.
Sources
lambda text to frontend | AWS re:Post
AWS Transcribe Streaming error: HTTP/2 stream is abnormally aborted in mid-communication with result code 2 | AWS re:Post
websocket connection | AWS re:Post