Adding custom claims return error auth/invalid-email:The email address is improperly formatted with Firebase Functions

I'm trying to add a custom user claims on my vue project so I can change what a user can see/do. The way it works is I have an input field that I'll enter an email from a user and it will add an admin claim to it. When I went to test it, I got an object back with the error "errorInfo: Object { code: "auth/invalid-email", message: "The email address is improperly formatted." }

I already tried looking for what is wrong in my code but from the examples I found, the code seems to be right.

I'm submitting a test@test.com email which I have as an example and I checked the vue.js devtools and I'm passing a string with test@test.com

Here is my index.js functions code

const functions = require("firebase-functions");
const admin = require("firebase-admin");
admin.initializeApp();

exports.addAdminRole = functions.https.onCall(async (data, context) => {
  //get user and add custom claim (admin)
  try {
    const user = await admin.auth().getUserByEmail(data.email);
    await admin.auth().setCustomUserClaims(user.uid, {
      admin: true
    });
    return {
      message: `Success! has been made admin`
    };
  } catch (err) {
    return err;
  }
});

And here is my vue component where I'm calling the function

<template>
  <div class="home">
    <h3>Welcome to Site</h3>

    <h3>Add user to admin</h3>
    <div class="row">
      <form @submit.prevent="addAdmin()" class="col s12">
        <div class="row">
          <div class="input-field col s12">
            <input type="email" v-model="email" required />
            <label>Email</label>
          </div>
        </div>
        <button type="submit" class="btn">Submit</button>
        <router-link to="/members" class="btn grey">Cancel</router-link>
      </form>
    </div>
  </div>
</template>

<script>
import { db, fc } from "../data/firebaseInit";
export default {
  name: "home",
  data() {
    return {
      email: null
    };
  },
  methods: {
    addAdmin() {
      const addAdminRole = fc.httpsCallable("addAdminRole");
      addAdminRole(this.email).then(result => {
        console.log(result);
      });
    }
  }
};
</script>