dbx.auth not working / getAccessTokenFromCode giving 400 response?

I'm trying to access the `getAccessTokenFromCode` method and I keep receiving a 400 error. On top of that, I can't seem to write the code and get it to work in the way it's written in the Auth example from the JavaScript SDK. `dbx.auth` does not work for me whether I construct an instance of Dropbox or DropboxAuth.

When i call `dbx.GetAccessTokenFromCode(redirectURI, code)`, I get a 400 response. I'm using the latest version (9.2.0). Furthermore, I read that `getAccessTokenFromCode` accepts null as a value in redirect uri as of version 5.0 and that doesn't work for me here either. Any help is so much appreciated.  Thanks! 

Example (Leaving a lot out since all I want to show is that token.result.refresh_token doesn't exist for me, just token.result.

const dbx = new Dropbox(config);

dbx.auth
.getAccessTokenFromCode(redirectUri, code)
.then(token => {
console.log(`Token Result:${JSON.stringify(token)}`);
dbx.auth.setRefreshToken(token.result.refresh_token);
dbx
.usersGetCurrentAccount()
.then(response => {
console.log('response', response);
})

 What I have to do is use the DropboxAuth class - which still doesn't work. (I'm using TypeScript, if it matters) 
const dbx = new DropboxAuth(config)

try {
const data = await dbx.getAccessTokenFromCode('some redirectURL',code)
} catch (err){
console.log(err.message)
}