node-oidc-provider /token method failing with 500 all the time

Question

Implemented basic setup of node-oidc-provider from this github example with mongo adapter.

When deployed under a https it got worked earlier, however when tried to deploy the same code in a different server, getting the error for token endpoint request.

added listener to provider and attached logs too.

  provider.addListener('server_error', (etx, error) => {
    console.error(JSON.stringify(error, null, 2));
  });

{
  "request": {
    "method": "POST",
    "url": "/token",
    "header": {
      "host": "--hosted app url--", 
      "x-forwarded-proto": "https",
      "x-real-ip": "--private-ip--",
      "x-forwarded-for": "--private-ip--",
      "connection": "close",
      "content-length": "311",
      "sec-ch-ua": "\"Not A(Brand\";v=\"99\", \"Google Chrome\";v=\"121\", \"Chromium\";v=\"121\"",
      "accept": "application/json",
      "content-type": "application/x-www-form-urlencoded",
      "sec-ch-ua-mobile": "?0",
      "user-agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0.0.0 Safari/537.36",
      "sec-ch-ua-platform": "\"macOS\"",
      "origin": "--requested web app url--",
      "sec-fetch-site": "same-site",
      "sec-fetch-mode": "cors",
      "sec-fetch-dest": "empty",
      "referer": "--requested web app url--",
      "accept-encoding": "gzip, deflate, br",
      "accept-language": "en-GB,en-US;q=0.9,en;q=0.8"
    }
  },
  "response": {
    "status": 500,
    "message": "Internal Server Error",
    "header": {
      "content-security-policy": "default-src 'self';base-uri 'self';font-src 'self' https: data:;frame-ancestors 'self';img-src 'self' data:;object-src 'none';script-src 'self';script-src-attr 'none';style-src 'self' https: 'unsafe-inline';upgrade-insecure-requests",
      "cross-origin-embedder-policy": "require-corp",
      "cross-origin-opener-policy": "same-origin",
      "cross-origin-resource-policy": "*",
      "x-dns-prefetch-control": "off",
      "x-frame-options": "SAMEORIGIN",
      "strict-transport-security": "max-age=15552000; includeSubDomains",
      "x-download-options": "noopen",
      "x-content-type-options": "nosniff",
      "origin-agent-cluster": "?1",
      "x-permitted-cross-domain-policies": "none",
      "referrer-policy": "no-referrer",
      "x-xss-protection": "0",
      "vary": "Origin",
      "access-control-allow-origin": "--requested web app url--",
      "access-control-allow-credentials": "true",
      "cache-control": "no-store",
      "content-type": "application/json; charset=utf-8"
    }
  },
  "app": {
    "subdomainOffset": 2,
    "proxy": true,
    "env": "production"
  },
  "originalUrl": "/token",
  "req": "<original node req>",
  "res": "<original node res>",
  "socket": "<original node socket>"
}

In the existing server sometimes we are getting

MongoServerError: E11000 duplicate key error collection: basemodels index: payload.grantId_1 dup key: { payload.grantId: "F5DIll55oARfHVxRdgoUWFFe8XbQQ0H8_FijtT3KB9_" }
  keyPattern: { 'payload.grantId': 1 },
  keyValue: { 'payload.grantId': 'F5DIll55oARfHVxRdgoUWFFe8XbQQ0H8_FijtT3KB9_' },

  Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
      at new NodeError (node:internal/errors:405:5)
      at ServerResponse.setHeader (node:_http_outgoing:648:11)
      at Cookies.set (/app/node_modules/cookies/index.js:148:13)
      at ContextSession.save (/app/node_modules/koa-session/lib/context.js:341:22)
      at ContextSession.commit (/app/node_modules/koa-session/lib/context.js:244:16)
      at session (/app/node_modules/koa-session/index.js:46:20)
      at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
      at async cors (/app/node_modules/@koa/cors/index.js:61:32)

Please let me know if I missed anything.