unable to get data using laravel when calling invokeAgent aws bedrock runtime

[GuruVasudevan]

Laravel call:
public function retrieveAgent()
{
try {
$result = $this->bedrockAgentRuntimeClient->invokeAgent([
'agentAliasId' => 'D4ME83NEPO',
'agentId' => '0O7BWE0V4H',
'sessionId' => 'abbc',
'inputText' => 'whchi country won soccer in 2023?',
'enableTrace' => true,
]);

        return $result;
    }
    catch(\Exception $ex) {
        return response()->json(['error' => $ex->getMessage()], Response::HTTP_INTERNAL_SERVER_ERROR);
    }
}

Response:
Model Data

Data can be retrieved from the model object using the get() method of the
model (e.g., $result->get($key)) or "accessing the result like an
associative array (e.g. $result['key']). You can also execute JMESPath
expressions on the result data using the search() method.

{
"completion": {},
"contentType": "application/json",
"sessionId": "abbc",
"@metadata": {
"statusCode": 200,
"effectiveUri":
"https://bedrock-agent-runtime.us-east-1.amazonaws.com/agents/0O7BWE0V4H/agentAliases/D4ME83NEPO/sessions/abbc/text",
"headers": {
"date": "Thu, 18 Apr 2024 16:43:37 GMT",
"content-type": "application/json",
"transfer-encoding": "chunked",
"connection": "keep-alive",
"x-amzn-requestid": "68adf488-af61-43e2-b162-90aa1df88689",
"x-amz-bedrock-agent-session-id": "abbc",
"x-amzn-bedrock-agent-content-type": "application/json"
},
"transferStats": {
"http": [
[]
]
}
}
}

Http Status code: 200, but no data being returned. please let me know what might be the cause.