are you using a client component or mounting the component that is doing the fetch as a child of a client component?

can you post the code that does the fetching

Where are u actually hosting the nextjs app and express apps? On vercel?
And are u seeing the GET to /categories actually being made in ur browser devtools network tab? Or do u just see the error in the browser console

hi guys, thx for your reply,
mycontact page is a client component, but my ApiClient (where i make the axios call to the backend) is a server component
I'm hosting on a vps

the code is like
the page

import { useEffect, useState } from 'react'
import Link from 'next/link'
import { useRouter } from 'next/navigation'
import { apiClient } from '@/lib/api'

export function ClientNavbar() {
const router = useRouter()
...
useEffect(() => {
async function fetchCategories() {
try {
const response = await apiClient.getCategories()

the apiclient

import axios, { AxiosInstance } from 'axios'

class ApiClient {
private client: AxiosInstance

constructor() {
this.client = axios.create({
baseURL: process.env.NEXT_PUBLIC_API_URL,
withCredentials: true,
timeout: 30000,
})


this.client.interceptors.request.use((config) => {
if (typeof window !== 'undefined') {
// Parse cookies to get auth-store
const cookieString = document.cookie
.split('; ')
.find((row) => row.startsWith('auth-store='));

if (cookieString) {
try {
const token = cookieString.split('=')[1];
console.log('🔍 ApiClient - Token from cookie:', token);
if (token) {
config.headers.Authorization = Bearer ${token};
}
} catch (error) {
console.error('Error parsing auth-store cookie:', error);
}
}
else {
}
}
return config;
})

}

async getCategories() {
const response = await this.client.get('/categories')
return response.data
}
...


I fixed it by puting NEXT_PUBLIC_API_URL = mywebsite.com/api
But I still want to now why it executes on the browser ?
The goal that i want is that my api will be invisible from the outside, only my nextjs server component will be able to call through a localhost adress
I don't know if i made myself clear ?