Cannot add role to use using login flow

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We setup a login flow rule to automatically assign a role to a user that has client_name = DeveloperPortal in the user metadata but are getting the following error when we run a test call.

SanitizedError [APIError]: getaddrinfo ENOTFOUND null
    at /data/_verquire/_node16/@auth0/rule-utilities/0.2.0/node_modules/rest-facade/src/Client.js:402:25
    at Request.callback (/data/_verquire/_node16/@auth0/rule-utilities/0.2.0/node_modules/superagent/lib/node/index.js:905:3)
    at ClientRequest.<anonymous> (/data/_verquire/_node16/@auth0/rule-utilities/0.2.0/node_modules/superagent/lib/node/index.js:822:12)
    at ClientRequest.emit (node:events:527:28)
    at ClientRequest.emit (node:domain:475:12)
    at TLSSocket.socketErrorListener (node:_http_client:454:9)
    at TLSSocket.emit (node:events:527:28)
    at TLSSocket.emit (node:domain:475:12)
    at emitErrorNT (node:internal/streams/destroy:157:8)
    at emitErrorCloseNT (node:internal/streams/destroy:122:3) {
  statusCode: 'ENOTFOUND',
  requestInfo: { method: 'post', url: 'https://null' },
  originalError: Error: getaddrinfo ENOTFOUND null
      at GetAddrInfoReqWrap.onlookup [as oncomplete] (node:dns:71:26)
      at GetAddrInfoReqWrap.callbackTrampoline (node:internal/async_hooks:130:17) {
    errno: -3008,
    code: 'ENOTFOUND',
    syscall: 'getaddrinfo',
    hostname: 'null',
    response: undefined
  }
}

here is the rule we created.

/**
* Handler that will be called during the execution of a PostLogin flow.
*
* @param {Event} event - Details about the user and the context in which they are logging in.
* @param {PostLoginAPI} api - Interface whose methods can be used to change the behavior of the login.
*/

exports.onExecutePostLogin = async (event, api) => {


  const namespace = "https://xxxxx.com";

  const ManagementClient = require("auth0").ManagementClient;

  const management = new ManagementClient({
    domain: event.secrets.domain,
    clientId: event.secrets.clientId,
    clientSecret: event.secrets.clientSecret,
    scope: "read:roles create:roles update:roles",
  });

  const devportalRole = { id :'xxxx'}; // This id must be a variable!!
  var data = { "users" : [ event.user.user_id]};

  try {
    // if (event.authorization) {
      if (!event.user.email_verified) {
        return;
      } else if (event.user.user_metadata.client_name === "DeveloperPortal") {
          api.idToken.setCustomClaim(`${namespace}/roles`, ['DeveloperPortal - User']);
          api.accessToken.setCustomClaim(`${namespace}/roles`, ['DeveloperPortal - User']);
          await management.roles.assignUsers(devportalRole, data);
      }
    // }
  } catch (e) {
    console.log(e);
  }

};
  
  /**
  * Handler that will be invoked when this action is resuming after an external redirect. If your
  * onExecutePostLogin function does not perform a redirect, this function can be safely ignored.
  *
  * @param {Event} event - Details about the user and the context in which they are logging in.
  * @param {PostLoginAPI} api - Interface whose methods can be used to change the behavior of the login.
  */
  // exports.onContinuePostLogin = async (event, api) => {
  // };

Not sure where my issue is, could use some help with the script…