issue with client-appstream

hello all,

i have a small tsx file that i am wanting to create an appstream url:

import * as AWS from "@aws-sdk/client-appstream";

const client = new AWS.AppStreamClient({ region: "eu-west-2" });

export default function AppStreamURI() {

  const params = {
    "FleetName": "Windows-Fleet",
    "StackName": "Windows-Stack",
    "UserId": "someone@gmail.com",
    "ApplicationArn": "null",
  }  

  const command = new AWS.AssociateApplicationFleetCommand(params);

  client.send(command).then(
    (data) => {
      console.log(data)
    },
    (error) => {
      console.error(error)
    }
  )

  return(
    <div>Hello</div>
  )
}

The ApplicationArn is added as it was throwing an error saying this was needed, but couldnt find it noted in the aws documentation (?).

I have aws config in vscode and is working on Cognito connection and what-not.

I am getting the following error, which i am hoping someone can assist me with:

Error: Credential is missing
    at SignatureV4.credentialProvider (runtimeConfig.browser.js:23:1)
    at SignatureV4.signRequest (SignatureV4.js:83:1)
    at SignatureV4.sign (SignatureV4.js:52:1)
    at middleware.js:12:1
    at async StandardRetryStrategy.retry (StandardRetryStrategy.js:47:1)
    at async loggerMiddleware.js:2:1 undefined

I am using React with "@aws-sdk/client-appstream": "^3.226.0"