How to fix Error: UNSUPPORTED_PROTOCOL: TLS version mismatch (incompatible protocol versions) in Node.js

node -p "process.versions.openssl"
node -p "require('tls').DEFAULT_MIN_VERSION"
node -p "require('tls').DEFAULT_MAX_VERSION"

# Test TLS 1.0
openssl s_client -connect example.com:443 -tls1

# Test TLS 1.1
openssl s_client -connect example.com:443 -tls1_1

# Test TLS 1.2
openssl s_client -connect example.com:443 -tls1_2

# Test TLS 1.3
openssl s_client -connect example.com:443 -tls1_3

const https = require('https');

const options = {
  hostname: 'example.com',
  port: 443,
  path: '/',
  method: 'GET',
  // Set minimum TLS version (e.g., to allow TLS 1.0 for legacy servers)
  minVersion: 'TLSv1',
  // Or set a specific secure protocol
  // secureProtocol: 'TLSv1_2_method'
};

https.request(options, (res) => {
  console.log('Connection successful');
}).end();

const https = require('https');

const agent = new https.Agent({
  minVersion: 'TLSv1.2',
  maxVersion: 'TLSv1.3'
});

https.get('https://example.com', { agent }, (res) => {
  console.log('Connected with TLS version:', res.socket.getProtocol());
});

const axios = require('axios');
const https = require('https');

const instance = axios.create({
  httpsAgent: new https.Agent({
    minVersion: 'TLSv1.2'
  })
});

instance.get('https://example.com')
  .then(response => console.log('Success'))
  .catch(error => console.error('Error:', error.message));

node --tls-min-v1.0 app.js

node --tls-min-v1.2 app.js

node --tls-max-v1.2 app.js

node --tls-min-v1.0 --tls-max-v1.2 app.js

{
  "scripts": {
    "start": "node --tls-min-v1.0 app.js"
  }
}

ssl_protocols TLSv1.2 TLSv1.3;
ssl_ciphers HIGH:!aNULL:!MD5;

SSLProtocol -all +TLSv1.2 +TLSv1.3
SSLCipherSuite HIGH:!aNULL:!MD5

const https = require('https');
const fs = require('fs');

const options = {
  key: fs.readFileSync('server-key.pem'),
  cert: fs.readFileSync('server-cert.pem'),
  minVersion: 'TLSv1.2',
  maxVersion: 'TLSv1.3'
};

https.createServer(options, (req, res) => {
  res.writeHead(200);
  res.end('Secure connection\n');
}).listen(443);

const https = require('https');

const options = {
  hostname: 'example.com',
  port: 443,
  path: '/',
  method: 'GET'
};

const req = https.request(options, (res) => {
  console.log('Connection successful!');
  console.log('TLS Version:', res.socket.getProtocol());
  console.log('Cipher:', res.socket.getCipher());

  res.on('data', (d) => {
    process.stdout.write(d);
  });
});

req.on('error', (e) => {
  console.error('Connection failed:', e.message);
});

req.end();

Connection successful!
TLS Version: TLSv1.2
Cipher: { name: 'ECDHE-RSA-AES128-GCM-SHA256', version: 'TLSv1.2' }