Next.JS - localhost is prepended when making external API call - next.js

Question

I got a simple Next app where I'm making an external API call to fetch some data. This worked perfectly fine until a couple days ago - when the app is making an API request, I can see in the network tab that the URL that it's trying to call, got Next app's address (localhost:3000) prepended in front of the actual URL that needs to be called e.g.: instead of http://{serverAddress}/api/articles it is calling http://localhost:3000/{serverAddress}/api/articles and this request resolves into 404 Not Found.
To make the API call, I'm using fetch. Before making the request, I've logged the URL that was passed into fetch and it was correct URL that I need. I also confirmed my API is working as expected by making the request to the expected URL using Postman.
I haven't tried using other library like axios to make this request because simply it doesn't make sense considering my app was working perfectly fine only using fetch so I want to understand why is this happening for my future experience.
I haven't made any code changes since my app was working, however, I was Dockerizing my services so I installed Docker and WSL2 with Ubuntu. I was deploying those containers on another machine, now both, the API I'm calling and Next app are running on my development machine directly when this issue is happening.
I saw this post, I confirmed I don't have any whitespaces in the URL, however, as one comment mentions, I installed WSL2, however, I am not running the app via WSL terminal. Also, I've tried executing wsl --shutdown to see if that helps, unfortunately the issue still persists. If this is the cause of the issue, how can I fix it? Uninstall WSL2? If not, what might be another possible cause for the issue?
Thanks in advance.
EDIT:
The code I'm using to call fetch:
fetcher.js
export const fetcher = (path, options) =>
fetch(`${process.env.NEXT_PUBLIC_API_URL}${path}`, options)
.then(res => res.json());
useArticles.js
import { useSWRInfinite } from 'swr';
import { fetcher } from '../../utils/fetcher';
const getKey = (pageIndex, previousPageData, pageSize) => {
if (previousPageData && !previousPageData.length) return null;
return `/api/articles?page=${pageIndex}&limit=${pageSize}`;
};
export default function useArticles(pageSize) {
const { data, error, isValidating, size, setSize } = useSWRInfinite(
(pageIndex, previousPageData) =>
getKey(pageIndex, previousPageData, pageSize),
fetcher
);
return {
data,
error,
isValidating,
size,
setSize
};
}

Answer 1

You might be missing protocol (http/https) in your API call. Fetch by default calls the host server URL unless you provide the protocol name.
Either put it into env variable:
NEXT_PUBLIC_API_URL=http://server_address
Or prefix your fetch call with the protocol name:
fetch(`http://${process.env.NEXT_PUBLIC_API_URL}${path}`, options)