Uncaught in Promise handlerror (Axios Error) in ReactJS

So I am making a blog application. I have used an axios inceptors concept name is api.js -

import axios from 'axios';
import { API_NOTIFICATION_MESSAGES, SERVICE_URLS } from '../constants/config';

const API_URL = 'http://localhost:8000';
const axiosInstance = axios.create({
  baseURL: API_URL,
  timeout: 10000,
  headers: {
    'content-type': 'application/json',
  },
});

axiosInstance.interceptors.request.use(
  function (config) {
    // if (config.TYPE.params) {
    //     config.params = config.TYPE.params
    // } else if (config.TYPE.query) {
    //     config.url = config.url + '/' + config.TYPE.query;
    // }
    return config;
  },
  function (error) {
    return Promise.reject(error);
  },
);

axiosInstance.interceptors.response.use(
  function (response) {
    // Stop global loader here
    return processResponse(response);
  },
  function (error) {
    // Stop global loader here
    return Promise.reject(processError(error));
  },
);

///////////////////////////////
// If success -> returns { isSuccess: true, data: object }
// If fail -> returns { isFailure: true, status: string, msg: string, code: int }
//////////////////////////////
const processResponse = (response) => {
  if (response?.status === 200) {
    return { isSuccess: true, data: response.data };
  } else {
    return {
      isFailure: true,
      status: response?.status,
      msg: response?.msg,
      code: response?.code,
    };
  }
};

///////////////////////////////
// If success -> returns { isSuccess: true, data: object }
// If fail -> returns { isError: true, status: string, msg: string, code: int }
//////////////////////////////
const processError = async (error) => {
  if (error.response) {
    //request made and server responded wit a status other than that falls out of the range 2.x.x
    console.log('ERROR IN RESPONSE: ', error.toJSON());
    return {
      isError: true,
      msg: API_NOTIFICATION_MESSAGES.responseFailure,
      code: error.response.status,
    };
  } else if (error.request) {
    //request made but no response was received
    console.log('ERROR IN RESPONSE: ', error.toJSON());
    return {
      isError: true,
      msg: API_NOTIFICATION_MESSAGES.requestFailure,
      code: '',
    };
  } else {
    //something happended in writting up request that triggers an error
    console.log('ERROR IN RESPONSE: ', error.toJSON());
    return {
      isError: true,
      msg: API_NOTIFICATION_MESSAGES.networkError,
      code: '',
    };
  }
};

const API = {};
for (const [key, value] of Object.entries(SERVICE_URLS)) {
  API[key] = (body, showUploadProgress, showDownloadProgress) =>
    axiosInstance({
      method: value.method,
      url: value.url,
      data: body,
      responseType: value.responseType,
      onUploadProgress: function (progressEvent) {
        if (showUploadProgress) {
          let percentCompleted = Math.round(
            (progressEvent.loaded * 100) / progressEvent.total,
          );
          showUploadProgress(percentCompleted);
        }
      },
      onDownloadProgress: function (progressEvent) {
        if (showDownloadProgress) {
          let percentCompleted = Math.round(
            (progressEvent.loaded * 100) / progressEvent.total,
          );
          showDownloadProgress(percentCompleted);
        }
      },
    });
}

export { API };

This is my config.js page -

// API NOTIFICATION MESSAGES
export const API_NOTIFICATION_MESSAGES = {
  loading: {
    title: 'Loading...',
    message: 'Data is being loaded. Please wait',
  },
  success: {
    title: 'Success',
    message: 'Data successfully loaded',
  },
  requestFailure: {
    title: 'Error!',
    message: 'An error occur while parsing request data',
  },
  responseFailure: {
    title: 'Error!',
    message:
      'An error occur while fetching response from server. Please try again',
  },
  networkError: {
    title: 'Error!',
    message:
      'Unable to connect to the server. Please check internet connectivity and try again.',
  },
};

// API SERVICE URL
// SAMPLE REQUEST
// NEED SERVICE CALL: { url: "/", method: "POST/GET/PUT/DELETE" }
export const SERVICE_URLS = {
  userLogin: { url: '/login', method: 'POST' },
  userSignup: { url: '/signup', method: 'POST' },
  getAllPosts: { url: '/posts', method: 'GET', params: true },
  getRefreshToken: { url: '/token', method: 'POST' },
  uploadFile: { url: 'file/upload', method: 'POST' },
  createPost: { url: 'create', method: 'POST' },
  deletePost: { url: 'delete', method: 'DELETE', query: true },
  getPostById: { url: 'post', method: 'GET', query: true },
  newComment: { url: '/comment/new', method: 'POST' },
  getAllComments: { url: 'comments', method: 'GET', query: true },
  deleteComment: { url: 'comment/delete', method: 'DELETE', query: true },
  updatePost: { url: 'update', method: 'PUT', query: true },
};

Finally this is my Login.jsx page -

import { Box, TextField, Button, styled, Typography } from '@mui/material';
import { useState } from 'react';
import { API } from '../../service/api';

const Component = styled(Box)`
  width: 400px;
  margin: auto;
  box-shadow: 5px 2px 5px 2px rgb(0 0 0/ 0.6);
`;
const Image = styled('img')({
  width: 100,
  display: 'flex',
  margin: 'auto',
  padding: '50px 0 0',
});
const Wrapper = styled(Box)`
  padding: 25px 35px;
  display: flex;
  flex: 1;
  overflow: auto;
  flex-direction: column;
  & > div,
  & > button,
  & > p {
    margin-top: 20px;
  }
`;
const LoginButton = styled(Button)`
  text-transform: none;
  background: #fb641b;
  color: #fff;
  height: 48px;
  border-radius: 2px;
`;
const SignupButton = styled(Button)`
  text-transform: none;
  background: #fff;
  color: #2874f0;
  height: 48px;
  border-radius: 2px;
  box-shadow: 0 2px 4px 0 rgb(0 0 0 / 20%);
`;
const Text = styled(Typography)`
  color: #878787;
  font-size: 12px;
`;
const Error = styled(Typography)`
  font-size: 10px;
  color: #ff6161;
  line-height: 0;
  margin-top: 10px;
  font-weight: 600;
`;

const signupInitialValues = {
  name: '',
  username: '',
  password: '',
};

const Login = () => {
  const imageURL =
    'https://www.sesta.it/wp-content/uploads/2021/03/logo-blog-sesta-trasparente.png';

  const [signup, setSignup] = useState(signupInitialValues);
  const [error, showError] = useState('');
  const [account, toggleAccount] = useState('login');

  const onInputChange = (e) => {
    setSignup({ ...signup, [e.target.name]: e.target.value });
  };

  const signupUser = async () => {
    let response = await API.userSignup(signup);
    console.log(response);
    if (response.isSuccess) {
      showError('');
      setSignup(signupInitialValues);
      toggleAccount('login');
    } else {
      showError('Something went wrong! please try again later');
    }
  };

  const toggleSignup = () => {
    account === 'signup' ? toggleAccount('login') : toggleAccount('signup');
  };

  return (
    <Component>
      <Box>
        <Image src={imageURL} alt="login"></Image>
        {account === 'login' ? (
          <Wrapper>
            <TextField variant="filled" label="Enter Username" />
            <TextField variant="filled" label="Enter Password" />
            {error && <Error>{error}</Error>}
            <LoginButton variant="contained">LOGIN</LoginButton>
            <Text style={{ textAlign: 'center' }}>OR</Text>
            <SignupButton
              onClick={() => toggleSignup()}
              style={{ marginBottom: 50 }}
            >
              Create an account
            </SignupButton>
          </Wrapper>
        ) : (
          <Wrapper>
            <TextField
              variant="filled"
              onChange={(e) => onInputChange(e)}
              label="Enter Name"
            />
            <TextField
              variant="filled"
              onChange={(e) => onInputChange(e)}
              label="Enter Username"
            />
            <TextField
              variant="filled"
              onChange={(e) => onInputChange(e)}
              label="Enter Password"
            />
            {error && <Error>{error}</Error>}
            <SignupButton onClick={() => signupUser()}>SIGN UP</SignupButton>
            <Text style={{ textAlign: 'center' }}>OR</Text>
            <LoginButton variant="contained" onClick={() => toggleSignup()}>
              Already have an account
            </LoginButton>
          </Wrapper>
        )}
      </Box>
    </Component>
  );
};
export default Login;

Then, whenever I'm testing it by clicking sign up, it is showing this error.

Please resolve my issue.

I was trying to create user sign up successfully