Error self signed certificate in certificate chain nodemailer


The “self-signed certificate in certificate chain” error in Google Chrome appears when loading sites that use a self-signed SSL certificate. This error means that the site’s security certificate is not from a trusted source.

The cause of this error is that the site’s SSL certificate is not from a trusted source. When you visit a site that has a self-signed SSL certificate, you will see a warning message in your browser.

If you are the owner of the site, you can fix this problem by obtaining an SSL certificate from a trusted source and configuring your web server to use it.

What is an SSL Certificate?

SSL Certificates are small data files that digitally bind a cryptographic key to an organization’s details. When installed on a web server, it activates the padlock and the https protocol and allows secure connections from a web server to a browser. Typically, SSL is used to secure credit card transactions, data transfer and logins, and more recently is becoming the norm when securing browsing of social media sites.

What is a Self-Signed Certificate?

A self-signed certificate is an identity certificate that is signed by the same entity whose identity it certifies. That is, if Entity A says that Entity B is who Entity B says it is, and Entity A signs that assertion with its own private key, then that is a self-signed certificate for Entity B.

What are the Benefits of a Self-Signed Certificate?

A self-signed certificate is an inexpensive and convenient way to secure your site or web application. When you create a self-signed certificate, you are the only party that is responsible for verifying the identity of the site or application. This means that you don’t have to rely on a third-party Certificate Authority (CA) to verify the identity of your site or application.

How to Create a Self-Signed Certificate?

A self-signed certificate is an identification certificate that is not signed by a recognized certificate authority. This type of certificate is used for development or internal purposes where security is not a primary concern. You can create a self-signed certificate using the OpenSSL toolkit, which is available on most Unix and Linux platforms.

To create a self-signed certificate, you will first need to generate a private key. This can be done using the openssl genrsa command. The following command will generate a 2048-bit private key:

openssl genrsa -out example.key 2048

Once you have generated a private key, you can create a self-signed certificate using the openssl req command. This command will prompt you for several pieces of information that will be incorporated into your certificate. The most important piece of information is the common name, which must be set to the fully qualified domain name of your server (e.g., The following command will create a self-signed certificate valid for 365 days:

openssl req -new -x509 -days 365 -key example.key -out example.crt

How to Install a Self-Signed Certificate?

A self-signed certificate is an identification document that proves the authenticity of a website. It is signed by a Certificate Authority (CA), which is a trustworthy entity that verifies the identity of the website owner. The CA issues the certificate and encrypts it with a public key, which can be used to verify the identity of the website.

Self-signed certificates are not as secure as those signed by a CA, but they are much cheaper and easier to obtain. If you’re running a small website or blog, a self-signed certificate might be sufficient.

Installing a self-signed certificate is relatively easy. Follow these steps:

  1. Generate a private key and public certificate using OpenSSL.
  2. Configure your web server to use the new key and certificate.
  3. Test your installation to make sure everything is working correctly.
    How to Use a Self-Signed Certificate?

    If you want to use a self-signed certificate, you will need to set the NODEMAILER_SELFSIGNED environment variable to true. You can do this either in your .env file or in the environment in which you are running your node application. For example, if you are using Docker, you can set the environment variable in your Dockerfile.

Once you have set the NODEMAILER_SELFSIGNED environment variable, you can use a self-signed certificate by passing the ca: fs.readFileSync(“cert.pem”) option to the mailer options when initializing nodemailer.

How to Fix an Error Self Signed Certificate in Certificate Chain?

If you are receiving the error “self signed certificate in certificate chain” in your nodemailer application, there are a few potential causes.

First, check to make sure that you are using a valid SSL certificate. If you are using a self-signed certificate, you will need to add the CA (Certificate Authority) to your list of trusted CAs in order to avoid this error.

Next, check your application settings to make sure that you are not specifying an invalid hostname or port number. If you are using Gmail, for example, be sure that you are specifying the correct SMTP server address ( and port (587).

Finally, if all else fails, try manually setting the NODE_TLS_REJECT_UNAUTHORIZED environment variable to 0. This will bypass security checks for TLS/SSL certificates and is not recommended for production environments.


Thank you for taking the time to read this guide. I hope that it has helped you understand the different types of coffee roasts available. Remember, the perfect roast is a personal choice. Experiment with different roasts and find the one that suits your taste buds the best!

Leave a Reply

Your email address will not be published.