# Firebase Auth: auth/internal-error
> Firebase auth/internal-error is a catch-all. Read the full error message first: a blocking function that threw an error is a known cause.
Canonical: https://app369.com/fix/firebase-auth-internal-error/
Last updated: 2026-11-09
auth/internal-error is the Firebase Auth code for an unexpected error. Firebase’s Admin SDK docs describe it as an unexpected error on the Authentication server and say the message should carry more detail, so the message is where to look first.
**Short answer**
Log error.message, not only error.code. If it mentions a Cloud Function, a blocking function such as beforeUserCreated or beforeUserSignedIn threw an error: fix that function. A blocking function that runs past 7 seconds also fails the sign-in, so keep it fast. If nothing points to your code and it keeps happening, report it to Firebase support with the full message.
Rather not fix it yourself? [**App Fix Ticket**](https://app369.com/fixed-price/flutter-firebase-bug-fix/) starts with a fixed-price diagnosis, then a fixed price for the fix before any fix work.
## **What hides behind auth/internal-error, and the fix**
1. 01 ### **A blocking function threw an error**
> “Regardless of whether you use a default or custom message, Cloud Functions wraps the error and returns it to the client as an internal error.” [**Firebase, Extend Firebase Authentication with blocking functions**](https://firebase.google.com/docs/auth/extend-with-blocking-functions) An HttpsError thrown in a beforeUserCreated or beforeUserSignedIn function stops the sign-up or sign-in. Firebase returns it to the app as an internal error, with the function’s message inside, so show that message to the user.```
try {
await createUserWithEmailAndPassword(auth, email, password);
} catch (error) {
console.error(error.code, error.message); // the message holds the reason
if (error.message.includes('Cloud Function')) {
showError('Sign-up was blocked. Check the details and try again.');
}
}
```
2. 02 ### **A blocking function ran past 7 seconds**
> “Your function must respond within 7 seconds. After 7 seconds, Firebase Authentication returns an error, and the client operation fails.” [**Firebase, Extend Firebase Authentication with blocking functions**](https://firebase.google.com/docs/auth/extend-with-blocking-functions) A slow database call or outside API in the function can push it past the limit, and every sign-in or sign-up that runs it then fails with an error. Firebase does not say which code that error carries, so read the message. Move slow work to a normal function that runs after sign-up, and keep the blocking function short.
3. 03 ### **The server hit an unexpected error**
> “The error message should contain the response from the Authentication server containing additional information.” [**Firebase, Admin Authentication API errors (auth/internal-error)**](https://firebase.google.com/docs/auth/admin/errors) With no blocking function involved, read the full message from the server. If the same call keeps failing, send the message and the steps to reproduce it to Firebase support.
4. 04 ### **The app only logs the code** Also check: an error handler that shows “Something went wrong” and drops error.message hides the cause. Log the message to your error tracker before you change anything else.
Checked against the vendor’s docs on November 9, 2026: [Firebase docs: Admin Authentication API errors](https://firebase.google.com/docs/auth/admin/errors); [Firebase docs: Extend Firebase Authentication with blocking functions](https://firebase.google.com/docs/auth/extend-with-blocking-functions); [Firebase JS SDK reference: auth error codes](https://firebase.google.com/docs/reference/js/auth).
## **Rather hand it over?**
Fixed scope, fixed price, paid upfront. The work happens in writing; no call needed.
- [from $450**App Fix Ticket**One reproducible bug in an existing mobile or web app, diagnosed and fixed.**See scope and start**](https://app369.com/fixed-price/flutter-firebase-bug-fix/)
- [from $450**AI-Built App Rescue**A Lovable, Bolt or Cursor app checked end to end in 3 days, then its worst problems fixed at a fixed price.****No issues worth fixing, no charge.**** If the Launch Check finds nothing rated medium or higher, Simon refunds the full $450. You keep the report either way. This applies to the first 10 Launch Checks bought after October 30, 2026.**See scope and start**](https://app369.com/fixed-price/ai-app-rescue/)
[**All 127 Fiverr reviews**](https://app369.com/reviews/)
Related: [**Firebase Functions timeout**](https://app369.com/fix/firebase-functions-timeout/) · [**Firebase auth/operation-not-allowed**](https://app369.com/fix/firebase-auth-operation-not-allowed/) · [**Firebase auth/network-request-failed**](https://app369.com/fix/firebase-auth-network-request-failed/) · [**Firebase auth/billing-not-enabled**](https://app369.com/fix/firebase-auth-billing-not-enabled/)
Questions
## **More on this error**
**Is auth/internal-error a bug in my code? **+
Often, but not always. A blocking function in your project is one possible cause; if none is involved, the message from the Authentication server says more.
**Does it happen to every user? **+
If a blocking function times out or always throws, yes, every sign-up or sign-in that runs it fails. If only some users see it, look at what the function checks for those users.
**Can you fix it for me? **+
If one bug is the whole problem, the App Fix Ticket covers it: a written diagnosis first, then the fix. If the app has more going on, the Launch Check is a written check of the whole app. Each issue found is rated critical, high, medium or low, with where it is and how it was confirmed. No issues worth fixing, no charge. If the Launch Check finds nothing rated medium or higher, Simon refunds the full $450. You keep the report either way. This applies to the first 10 Launch Checks bought after October 30, 2026.
A different error?
## **Describe it and get a written quote**
Send the error and what you were doing. You get a written scope, a fixed price and a timeline; Simon replies by email, usually within one business day.
[**Describe your problem **→](https://app369.com/contact/) [**All fixes**](https://app369.com/fix/)