Is it possible to chat with an AWS Connect Agent using an external resource and Lambda?

I have a Lambda function that has the correct permissions for Connect to start a chat and the chat is not going to the flow. There is nothing in cloudwatch except the 200 response I provided below. I grabbed the ContactFlowID and the InstanceID from the "show additional information" menu in the Flow editor screen and I also have another automation that can trigger a phone call with the flow via lambda which works, but chat doesn't. Any ideas?

I have multiple use cases for this doing different things, but would like to start with just a basic "hello world" to get a POC built.

import boto3

connect_client = boto3.client('connect')

def lambda_handler(event, context):

    try:
        response = connect_client.start_chat_contact(
            ContactFlowId = 'myflowID',
            InstanceId= 'myinstanceID',
            ParticipantDetails={'DisplayName': 'Customer'},
            InitialMessage={
                'ContentType': 'text/plain',
                'Content': 'bruh'
            }
        )
        print("Chat contact started:", response)
    except Exception as e:
        print("Error starting chat contact:", e)
        raise e

    return {
        'statusCode': 200,
        'body': 'Chat contact initiated successfully'
    }

And here is the response..

Chat contact started: {'ResponseMetadata': {'RequestId': 'requestIDhere', 'HTTPStatusCode': 200, 'HTTPHeaders': {'date': 'Wed, 08 Nov 2023 14:12:27 GMT', 'content-type': 'application/json', 'content-length': '787', 'connection': 'keep-alive', 'x-amzn-requestid': 'someimportantIDnumber', 'access-control-allow-origin': '*', 'access-control-allow-headers': 'Content-Type,X-Amz-Date,Authorization,X-Api-Key,X-Amz-Security-Token', 'x-amz-apigw-id': 'OMdlEGSblah=', 'access-control-allow-methods': 'GET,OPTIONS,POST', 'access-control-expose-headers': 'x-amzn-RequestId,x-amzn-ErrorType', 'x-amzn-trace-id': 'Root=1-somenumbersandletters'}, 'RetryAttempts': 0}, 'ContactId': 'contactIDhere', 'ParticipantId': 'participantIDhere', 'ParticipantToken': 'blahblahblahmytokenblahblah='}

Here is my test flow.