David•9mo ago

"fetch failed" when building

Hi, we are running into an issue where building our production next app causes "fetch failed" errors for every page that is being generated. We have ssr set to false. How can we debug this?

 TRPCClientError: fetch failed
     at TRPCClientError.from (file:///home/david/mrb-docker-dev/www/mrb-monorepo/node_modules/.pnpm/@trpc+client@10.43.3_@trpc+server@10.43.3/node_modules/@trpc/client/dist/TRPCClientError-0de4d231.mjs:37:16)
     at file:///home/david/mrb-docker-dev/www/mrb-monorepo/node_modules/.pnpm/@trpc+client@10.43.3_@trpc+server@10.43.3/node_modules/@trpc/client/dist/httpUtils-f58ceda1.mjs:128:36
     at process.processTicksAndRejections (node:internal/process/task_queues:95:5) {
   meta: {},
   shape: undefined,
   data: undefined,
   [cause]: TypeError: fetch failed
       at Object.fetch (node:internal/deps/undici/undici:11372:11)
       at process.processTicksAndRejections (node:internal/process/task_queues:95:5) {
     cause: AggregateError
         at internalConnectMultiple (node:net:1114:18)
         at afterConnectMultiple (node:net:1667:5) {
       code: 'ECONNREFUSED',
        ]: [Array]
     }
   }
 }

 TRPCClientError: fetch failed
     at TRPCClientError.from (file:///home/david/mrb-docker-dev/www/mrb-monorepo/node_modules/.pnpm/@trpc+client@10.43.3_@trpc+server@10.43.3/node_modules/@trpc/client/dist/TRPCClientError-0de4d231.mjs:37:16)
     at file:///home/david/mrb-docker-dev/www/mrb-monorepo/node_modules/.pnpm/@trpc+client@10.43.3_@trpc+server@10.43.3/node_modules/@trpc/client/dist/httpUtils-f58ceda1.mjs:128:36
     at process.processTicksAndRejections (node:internal/process/task_queues:95:5) {
   meta: {},
   shape: undefined,
   data: undefined,
   [cause]: TypeError: fetch failed
       at Object.fetch (node:internal/deps/undici/undici:11372:11)
       at process.processTicksAndRejections (node:internal/process/task_queues:95:5) {
     cause: AggregateError
         at internalConnectMultiple (node:net:1114:18)
         at afterConnectMultiple (node:net:1667:5) {
       code: 'ECONNREFUSED',
        ]: [Array]
     }
   }
 }

11 Replies

David•9mo ago

We looked through github, this Discord server etc but all the solutions there don't work. Usually people actually want to be fetching as SSR or something but that is not the case with us so we don't understand why it even attempts to fetch something @Alex / KATT 🐱 Sorry, prefer not to tag people but been stuck at this for a while and i've got 0 clue how to continue. Any ideas?

Nick•9mo ago

Econnrefused probably means you’re pointing at the wrong uri

David•9mo ago

Appreciate the reply! This is during build though, it shouldn't be trying to fetch anything anyway, so im not sure at what point or why it is attempting to

Nick•9mo ago

That might mean you’ve put a fetch somewhere which calls on build NextJS and others do have APIs for this

David•9mo ago

Have looked through the commit where it started several times, I can't find anything that would cause this. All our fetches/hook calls are inside of components, nothing at the root level. Any idea how I could see a better stack trace that may lead to where its coming from? We did add prefetching in this commit on a page, but that is inside of a gssp.

Nick•9mo ago

I’d start restricting the problem space, print a lot more info from the api to see what the calls are and if the request is reaching it Try adding an onError to your adapter Then commenting out parts of the app if that doesn’t help, basically binary searching your components These types of issues are a pain but not something we can support massively with since it’s likely a setup mistake

David•9mo ago

Will try these things, thank you for the responses! So, some observations: The request is happening even before the browser renders, it does not show in the network tab in the browser, there are no cookies attached to the request when logging it on the server side Everything works in the background, as in the browser renders and makes a valid request etc. It does not end up in our root error boundary But any call to that specific procedure causes it. So if I only render that specific query it'll happen, even though I render it as we would anywhere else in some page. Only occurs for this specific procedure, taking out the code it errors on (cookie / auth stuff) fixes it, even though a bunch of other procedures use that same middleware So, we reverted the original PR for a while until we had more time to look at it. It starts when you change this:

// blitz way
return useQuery(ActiveLocalesQuery,

// blitz way
return useQuery(ActiveLocalesQuery,

to this:

return trpc.core.companyProduct.getActiveLocales.useSuspenseQuery(undefined, {

return trpc.core.companyProduct.getActiveLocales.useSuspenseQuery(undefined, {

1Sonny•9mo ago

@David I had this error a while ago too. Fixed by setting localhost to 127.0.0.1 in /etc/hosts in WSL

David•9mo ago

mostly confused because it shouldn't be fetching anything initially Changing it to useQuery instead of useSuspenseQuery solves it for now

Alex / KATT 🐱•9mo ago

ohhhhh i get what this is now if you use suspense it'll try to fetch the data on the first load on the server which is probably not what you want you prob want something like this if you're using suspense

import type { SuspenseProps } from 'react';
import React, { Suspense, useEffect, useState } from 'react';
import { Spinner } from '~/components/Spinner';

/**
 * Whether the app has ever mounted.
 * This is used to determine whether to render the fallback on the first render.
 */
let hasEverMounted = false;

/**
 * Suspense that doesn't render on the server.
 * - On server, it always renders the fallback.
 * - On client, it renders the fallback only on the first render.
 */
export function NoSSRSuspense(props: {
  children: React.ReactNode;
  /**
   * Fallback while loading.
   * @default <PageSpinner />
   */
  fallback?: SuspenseProps['fallback'];
}) {
  const [isMounted, setIsMounted] = useState(hasEverMounted);
  useEffect(() => {
    setIsMounted(true);
    hasEverMounted = true;
  }, []);
  const fallback =
    props.fallback === undefined ? <Spinner /> : props.fallback;

  return (
    <>{isMounted ? <Suspense {...props} fallback={fallback} /> : fallback}</>
  );
}

import type { SuspenseProps } from 'react';
import React, { Suspense, useEffect, useState } from 'react';
import { Spinner } from '~/components/Spinner';

/**
 * Whether the app has ever mounted.
 * This is used to determine whether to render the fallback on the first render.
 */
let hasEverMounted = false;

/**
 * Suspense that doesn't render on the server.
 * - On server, it always renders the fallback.
 * - On client, it renders the fallback only on the first render.
 */
export function NoSSRSuspense(props: {
  children: React.ReactNode;
  /**
   * Fallback while loading.
   * @default <PageSpinner />
   */
  fallback?: SuspenseProps['fallback'];
}) {
  const [isMounted, setIsMounted] = useState(hasEverMounted);
  useEffect(() => {
    setIsMounted(true);
    hasEverMounted = true;
  }, []);
  const fallback =
    props.fallback === undefined ? <Spinner /> : props.fallback;

  return (
    <>{isMounted ? <Suspense {...props} fallback={fallback} /> : fallback}</>
  );
}

David•9mo ago

Will try this now! This works! Thank you so much! Do you know why this happens during build? And could it be related to the fact that those queries get called in _app , compared to everything else which is only called on a page