Unknown application error occurred

Start with the linked issue-reproduction repository, run yarn, and exercise api/login/checksecurityans as described. Trace the stack from api/login/checksecurityans.js through api/services/jwt-token-service.js and jsonwebtoken/sign.js; done means determining whether the reported PEM error is reproducible in jsonwebtoken or specific to the reproduction setup.

Description

I have been working with Vercel support to resolve an issue where the jsonwebtoken package is encountering an error, "Unknown application error occurred". Vercel has directed me to open an issue here.

Reproduction

https://github.com/vercel-support/issue-reproduction

Here are my steps.

1. Clone the repo https://github.com/vercel-support/issue-reproduction
2. run, "yarn"
3. run the code in the api/login/checksecurityans file
4. Open Postman and POST to localhost:3000/api/login/checksecurityans
5. Get this error if you ran the code using 'vercel dev'

Or if you ran the file using node you might see an error like this one

[POST] /api/login/checksecurityans
17:08:28:62
2021-03-22T22:08:28.686Z    6d89535a-42b6-4836-89cd-1de6611f75ea    ERROR    Unhandled Promise Rejection  {"errorType":"Runtime.UnhandledPromiseRejection","errorMessage":"Error: error:0909006C:PEM routines:get_name:no start line","reason":{"errorType":"Error","errorMessage":"error:0909006C:PEM routines:get_name:no start line","code":"ERR_OSSL_PEM_NO_START_LINE","library":"PEM routines","function":"get_name","reason":"no start line","stack":["Error: error:0909006C:PEM routines:get_name:no start line","    at Sign.sign (internal/crypto/sig.js:110:29)","    at Object.sign (/var/task/api/node_modules/jwa/index.js:152:45)","    at Object.jwsSign [as sign] (/var/task/api/node_modules/jws/lib/sign-stream.js:32:24)","    at Object.module.exports [as sign] (/var/task/api/node_modules/jsonwebtoken/sign.js:204:16)","    at JwtTokenService.generateJwt (/var/task/api/services/jwt-token-service.js:57:29)","    at checkSecurityAns (/var/task/api/login/checksecurityans.js:4:33)","    at Server.<anonymous> (/var/task/___vc_helpers.js:813:19)","    at Server.emit (events.js:315:20)","    at parserOnIncoming (_http_server.js:874:12)","    at HTTPParser.parserOnHeadersComplete (_http_common.js:126:17)"]},"promise":{},"stack":["Runtime.UnhandledPromiseRejection: Error: error:0909006C:PEM routines:get_name:no start line","    at process.<anonymous> (/var/runtime/index.js:35:15)","    at process.emit (events.js:327:22)","    at process.emit (/var/task/___vc_sourcemap_support.js:587:21)","    at processPromiseRejections (internal/process/promises.js:245:33)","    at processTicksAndRejections (internal/process/task_queues.js:94:32)"]}
Unknown application error occurred

I do have a package.json file and it does include jsonwebtoken.

Environment

"jsonwebtoken": "8.5.1"
Node v14