Callback from auth0 contains no parameters

Hi community!

I am trying to implement the callback as explained here: Add Login Using the Authorization Code Flow

My problem:
The request contains no query parameters, I cannot parse a “code” or “state”.
I have done the first step exactly, I have verified the params that are passed into the lock.
And this is how my endpoint code looks:
@GET
@Path(“authentication/callback”)
@Produces(MediaType.APPLICATION_JSON)
public Response authenticationCallback(@Context HttpServletRequest request,
@DefaultValue(“sample code”) @QueryParam(“code”) String code,
@DefaultValue(“sample state”) @QueryParam(“state”) String state) {…}”

I look through the request object, but see nothing remotely relevant.

Am I missing something?
Thanks in advance!

I was using a Single Page Application in my Client, and instead I needed a Web App