Webhook URL validation failed randomly after working for months

API and Webhooks
,
1

we have a user-manages oauth app that receives webhooks. It was working for months and suddenly the url validation fails. the endpoint is an aws node lambda function. I have checked the domain mapping, domain health, and certificate everything is good. post requests also work on postman. I have tried regenerating the secret token but no luck. Please advise webhook functionality is essential to our app. Here is the relevant bit of code from the lambda function.

if (request.event === 'endpoint.url_validation') {
            const hashForValidate = crypto.createHmac('sha256', zoomWebhookSecretToken)
                .update(request.payload.plainToken)
                .digest('hex');

            const responseBody = {
                plainToken: request.payload.plainToken,
                encryptedToken: hashForValidate
            };
            console.log('responseBody:', responseBody )
            return {
                statusCode: 200,
                headers: {
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify(responseBody)
            };
        }