Using Nextjs (getServerSideprops) with elasticsearch from lambda node causes an error - elasticsearch

Question

I use nextjs with elastic search cloud, also use amplify and lambda created from amplify rest api.
This is my function:
export async function getServerSideProps(context) {
let esItems;
try {
const { query } = context.query;
const apiName = 'APINAME';
const path = '/searchlist';
const myInit = {
response: true,
queryStringParameters: { query: query }
};
const response = await API.get(apiName, path, myInit);
esItems = response;
} catch (err) {
console.log(err)
}
return {
props: {
allProducts: esItems ? esItems.data.items : [],
}
};
}
I return 50 products from elastic and get this error:
502 ERROR
The request could not be satisfied.
The Lambda function returned invalid JSON: The JSON output is not parsable. We can't connect to the server for this app or website at this time. There might be too much traffic or a configuration error. Try again later, or contact the app or website owner.
If you provide content to customers through CloudFront, you can find steps to troubleshoot and help prevent this error by reviewing the CloudFront documentation.
This is lambda function:
app.get('/searchlist', async (req, res) => {
const { query } = req.query;
const client = new Client({
node: "https://elastic-cloud....",
auth: {
username: process.env.USERNAME,
password: process.env.PASSWORD
}
});
const searchQuery = {
query: {
multi_match: {
query: query,
type: "phrase",
fields: [
'manufacturerTypeDescription^8',
'manufacturerName^6',
'ean^4',
'_id^2',
]
}
}
}
const typeSearch = {
index: "product",
size: 50,
body: searchQuery
}
const r = await client.search(typeSearch);
const hits = r.body.hits;
const items = hits.hits.map((hit) => ({
_id: hit._id,
...hit._source,
}))
res.json({
success: 'get call succeed!',
items
});
});