How to pass expire token error in custom authoriser for API gateway response

Hi Team,
We are using following configuration.
Lambda :-

exports.handler =  async (event, context, callback) => {
    try {
        callback(null,policyData);
        return;
    } catch (err) {
      // Always accepts "Unauthorized".
        callback("Unauthorized");
        return;
    }
};

SAM template :-

ExpiredGatewayResponse:
    Type: 'AWS::ApiGateway::GatewayResponse'
    Properties:
      ResponseParameters:
        gatewayresponse.header.Access-Control-Allow-Origin: "'*'"
        gatewayresponse.header.Access-Control-Allow-Headers: "'*'"
      ResponseType: EXPIRED_TOKEN
      ResponseTemplates:
        application/json: |
          {
            "success":false,
            "message":"Token Expired"
          }
      RestApiId: !Ref ApiGatewayApi
      StatusCode: '401'
  AuthFailureGatewayResponse:
    Type: 'AWS::ApiGateway::GatewayResponse'
    Properties:
      ResponseParameters:
        gatewayresponse.header.Access-Control-Allow-Credentials: "'true'"
        gatewayresponse.header.Access-Control-Allow-Origin: !Ref CorsOriginUrl
        gatewayresponse.header.Access-Control-Allow-Headers: "'Content-Type,X-Amz-Date,Authorization,X-Api-Key,X-Amz-Security-Token'"
      ResponseType: UNAUTHORIZED
      RestApiId: !Ref ApiGatewayApi
      StatusCode: '401'

In above code its always return unauthorized error.
If we pass anything else other then "Unauthorized" in call back then its return the error (message:null).

Please suggest how can we pass any other error response type like expired token form custom authorizer and In SAM it will take the configuration "ExpiredGatewayResponse".

Thanks,
Dilip

Start by reproducing the custom authorizer behavior from the JavaScript handler and SAM template, comparing the Unauthorized callback with other callback errors and the configured EXPIRED_TOKEN GatewayResponse. Verify whether API Gateway can select that response type from a custom authorizer, then document the supported behavior or update the relevant example if a change is identified.