UnauthorizedError: jwt malformed error when authenticating - express

Question

Im using Auth0 for authenticating users for my react application.I have been trying to access resources on server side but I keep getting UnauthorizedError: jwt malformed as an Error.
I’ve followed a the following thread on the community forums: https://community.auth0.com/t/unauthorizederror-jwt-malformed-in-express-js/7352
Many users have suggested that the audience value from the guide is wrong. The audience given in the guide is https:///userinfo but it should be ‘https://.auth0.com/api/v2/’, I’ve made that change and the error is still there.
This has worked for some people but not for me.
This is the guide ive been following: https://auth0.com/blog/react-tutorial-building-and-securing-your-first-app/
const checkJwt = jwt({
secret: jwksRsa.expressJwtSecret({
cache: true,
rateLimit: true,
jwksRequestsPerMinute: 5,
jwksUri: `https://<domain>/.well-known/jwks.json`
}),
// Validate the audience and the issuer.
audience: "https://<something>/api/v2/",
issuer: `https://<something>/`,
algorithms: ["RS256"]
});
this is the code ive written on the express side.
this.auth0 = new auth0.WebAuth({
// the following three lines MUST be updated
domain: "<Domain>",
audience: "https://<Something>/api/v2/",
clientID: "clientID",
redirectUri: "http://localhost:3000/callback",
responseType: "token",
scope: "openid"
});
This is the code written on the frontend of the application.

Answer 1

One of our senior engineers had a good recommendation on this that I will share below:
If you haven't done so already you should perform these steps:
capture the token you receive; for example, using a console.log statement given this is in development.
review the captured token; does it look like a JWT?
if its a JWT and you can parse it at jwt.io then update the API to log the received token before trying to validate it; does the received
token match the one you expect?
In conclusion, try to take steps that allow you to gather a bit more
of information.