What causes "Failed to load server config" in hcengineering/platform?

Add a non-empty 'subject' string to the request body before sending.

hcengineering/platform · error · Error

Failed to load server config

Error message

Failed to load server config

What it means

The mail service HTTP endpoint in services/mail/pod-mail/src/main.ts rejects a POST to the send-mail route with HTTP 400 when the request body has no 'subject' field. handleSendMail validates required fields (text/html, subject, to, from) sequentially and returns the first missing one as { err: "'subject' is missing" }. This is a deliberate input validation guard, not an internal failure.

Source

Thrown at desktop/src/ui/preload.ts:42

    const newPath = path.slice(1)
    return `${host}${newPath}`
  } else {
    return `${host}${path}`
  }
}

async function loadServerConfig (url: string): Promise<any> {
  let retries = 1
  let res: Response | undefined

  while (true) {
    try {
      res = await fetch(url, {
        keepalive: true
      })
      if (res === undefined) {
        // In theory should never get here
        throw new Error('Failed to load server config')
      }
      break
    } catch (e) {
      retries++
      await new Promise((resolve) => setTimeout(resolve, 1000 * Math.min(5, retries)))
    }
  }

  return await res.json()
}

const openArg = (process.argv.find((it) => it.startsWith('--open=')) ?? '').split('--open=')[1]
console.log('Open passed', openArg)
let configPromise: Promise<Config> | undefined

const expose: IPCMainExposed = {
  setBadge: (badge: number) => {
    ipcRenderer.send(IpcMessage.SetBadge, badge)

View on GitHub (pinned to 63e28dc964)

Solutions

Add a non-empty 'subject' string to the request body before sending.
If subject is optional by design, pass an empty string or a placeholder like '(no subject)'.
Check the caller code that constructs the payload for undefined subject values being dropped by JSON.stringify.
Return the error to the user or log it client-side instead of retrying the same payload.

Example fix

// before
await fetch(mailUrl, { method: 'POST', body: JSON.stringify({ from, to, text }) })
// after
await fetch(mailUrl, { method: 'POST', body: JSON.stringify({ from, to, text, subject: subject ?? '(no subject)' }) })

Defensive patterns

Strategy: validation

Validate before calling

if (typeof subject !== 'string' || subject.length === 0) {
  throw new Error('subject is required before calling the mail endpoint')
}

Type guard

function hasSubject(body: unknown): body is { subject: string; [k: string]: unknown } {
  return typeof body === 'object' && body !== null && typeof (body as any).subject === 'string' && (body as any).subject.length > 0
}

Try / catch

const res = await fetch(mailUrl, { method: 'POST', body })
if (res.status === 400) {
  const { err } = await res.json()
  if (err === "'subject' is missing") {
    // surface a field-level validation message to the user instead of retrying
  }
}

Prevention

Validate all required mail fields (subject, to, from, text/html) at the call site before building the request.
Avoid undefined fields in payloads — JSON.stringify silently drops them; use explicit defaults like '(no subject)'.
Write a shared payload builder for mail requests so required fields are enforced in one place.

When it happens

Trigger: POSTing to the mail endpoint with a JSON body that includes text or html, to, and from, but omits the 'subject' property (or sends it as null/undefined after JSON serialization drops it).

Common situations: Callers building the request dynamically where subject comes from user input or an upstream record that lacks a title; automated notification senders that only set the body; JSON.stringify silently dropping undefined subject values.

Related errors

AI-assisted analysis of hcengineering/platform@63e28dc964 (2026-08-29). Data as JSON: /api/errors/de6e83a7958deddb. Report an issue: GitHub.