Emails are not sent out after deploying to Lamba function - node.js

Question

I'm using Nodemailer and SES to send out mails from my application, it works perfectly locally but doesn't work once I deploy to Lambda function, it returns with a "Endpoint request timed out" error message after it exceeds the 30 seconds API gateway time limit.
Note: The Lambda function has all the permissions required to send out SES mails.
I thought SES was the problem and I decided to use gmail instead, I got the same result. Checking my cloudwatch logs I find this error:
2022-11-16T06:54:23.547Z 6d967bf2-0837-4bd8-ae5f-011842656d15 INFO Error: Connection timeout
at SMTPConnection._formatError (/var/task/node_modules/nodemailer/lib/smtp-connection/index.js:790:19)
at SMTPConnection._onError (/var/task/node_modules/nodemailer/lib/smtp-connection/index.js:776:20)
at Timeout.<anonymous> (/var/task/node_modules/nodemailer/lib/smtp-connection/index.js:235:22)
at listOnTimeout (node:internal/timers:559:17)
at processTimers (node:internal/timers:502:7) {
code: 'ETIMEDOUT',
command: 'CONN'
}
Here's my function for sending out the mails, I have modified it so many times, I thought I was the one not structuring it properly.
const transporter = nodemailer.createTransport ({
service: 'gmail',
host: 'smtp.gmail.com',
port: 587,
secure: true,
auth: {
user: config.REACT_APP_EMAIL,
pass: config.REACT_APP_EMAIL_PASS,
},
});
const sendOutMail = async (receiver, emailSubject, body) => {
return transporter.sendMail({
from: config.REACT_APP_EMAIL,
to: receiver,
subject: emailSubject,
text: body,
html: '<div> ' + emailSubject + '</div>',
})
.then( results => {
console.log("Success:", results);
return true
})
.catch ( error => {
console.log("Error:", error);
return false
})
}
All modifications of my function works locally, but none works after I deploy

Answer 1

Since your lambda function runs inside a VPC, make sure you have internet access on this VPC. Otherwise you need to create a VPC Endpoint for SES so that your lambda can make that API call.
Here is the documentation for reference:
https://docs.aws.amazon.com/ses/latest/dg/send-email-set-up-vpc-endpoints.html