I encountered a TypeError: Only absolute URLs are supported error while tying to deploy a Next.js app both in Vercel and Netlify. In my app, I have a config file to avoid of absolute path errors, since data is fetched from the server. 
config.js
const dev = process.env.NODE_ENV !== "production";
export const server = dev
  ? "http://localhost:3000"
  : "https://next-js-next-app-pjjs4ka8d-grf.vercel.app";
The domain I picked from vercel when a random domain was generated before starting the deployment.
But I guess it's wrong and I must provide another url for deployment.
Here is how I am using the server url in the app from config file
in pages/article[id] file.
export const getStaticProps = async (context) => {
  const res = await fetch(`${server}/api/articles/${context.params.id}`);
  const article = await res.json();
  return {
    props: {
      article,
    },
  };
};
export const getStaticPaths = async () => {
  const res = await fetch(`${server}/api/articles/`);
  const articles = await res.json();
  const ids = articles.map((article) => article.id);
  const paths = ids.map((id) => ({ params: { id: id.toString() } }));
  return {
    fallback: "blocking",
    paths: paths,
  };
};
Error output in Vercel while trying to deploy
10:11:04.813    > Build error occurred
10:11:04.815    TypeError: Only absolute URLs are supported
10:11:04.815        at getNodeRequestOptions (/vercel/path0/node_modules/node-fetch/lib/index.js:1305:9)
10:11:04.815        at /vercel/path0/node_modules/node-fetch/lib/index.js:1410:19
10:11:04.815        at new Promise (<anonymous>)
10:11:04.815        at fetch (/vercel/path0/node_modules/node-fetch/lib/index.js:1407:9)
10:11:04.815        at getStaticPaths (/vercel/path0/.next/server/pages/article/[id].js:168:21)
10:11:04.815        at buildStaticPaths (/vercel/path0/node_modules/next/dist/build/utils.js:16:86)
10:11:04.815        at /vercel/path0/node_modules/next/dist/build/utils.js:26:628
10:11:04.815        at processTicksAndRejections (internal/process/task_queues.js:93:5)
10:11:04.815        at async Span.traceAsyncFn (/vercel/path0/node_modules/next/dist/telemetry/trace/trace.js:6:584) {
10:11:04.815      type: 'TypeError'
10:11:04.815    }
10:11:04.834    npm ERR! code ELIFECYCLE
10:11:04.834    npm ERR! errno 1
10:11:04.838    npm ERR! traversytutorial@0.1.0 build: `next build && next export`
10:11:04.838    npm ERR! Exit status 1
10:11:04.839    npm ERR! 
10:11:04.839    npm ERR! Failed at the traversytutorial@0.1.0 build script.
10:11:04.839    npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
10:11:04.846    npm ERR! A complete log of this run can be found in:
10:11:04.847    npm ERR!     /vercel/.npm/_logs/2021-06-18T08_11_04_839Z-debug.log
10:11:04.859    Error: Command "npm run build" exited with 1
Any help will be appreciated
