Why can I still sign in when sign-ups fail?

Turning off sign-ups only stops new accounts. Supabase says that when the setting is disabled, only existing users can sign in, so your own account keeps working while new users are refused.

Does turning sign-ups back on affect existing users?

No. It only lets new accounts be created again. After turning it on, test with an email address that has never signed up to the project.

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.

Supabase “Signups Not Allowed for This Instance”?

Supabase Auth errorSupabase: “Signups not allowed for this instance”

Existing users can still sign in, but every new sign-up fails with Signups not allowed for this instance, error code signup_disabled. New account creation is switched off for the project your app talks to. It is often one setting, turned off while testing or set in a local config file. Here’s where to look, in Supabase’s words, or hand it over at a fixed price.

Short answer

In the Supabase dashboard, open the Authentication settings for sign-ups and turn Allow new users to sign up back on for the project your production app uses. For email sign-ups, check the email provider is enabled too. When you run Supabase locally, set enable_signup = true in supabase/config.toml and restart. Then test a fresh sign-up.

Where sign-ups are switched off

01
Allow new users to sign up is off
“Users will be able to sign up. If this config is disabled, only existing users can sign in.” Supabase, General configuration
This project setting stops all new accounts while existing users keep signing in, which is why the app can look fine to you. Check it on the project your app’s Supabase URL points at, since staging and production are often separate projects.
02
The error code is signup_disabled
“Sign ups (new account creation) are disabled on the server.” Supabase, Auth error codes
Check error.code in your sign-up handler. signup_disabled means sign-ups are off for the whole project. email_provider_disabled means only email and password sign-up is off, and the fix is in the email provider’s settings.
03
Local Supabase has enable_signup set to false
“Allow/disallow new user signups to your project.” Supabase, CLI configuration
With the Supabase CLI, sign-ups follow supabase/config.toml, not the dashboard. Both enable_signup settings default to true, so look for one set to false, then restart the local stack.
```
[auth]
enable_signup = true

[auth.email]
enable_signup = true
```
04
Sign-ups were closed on purpose
Some apps close sign-ups so only invited users get in. If that was the plan, show people a clear message instead of a raw error, and add users by invite from the dashboard or a server-side admin call.

Checked against the vendor’s docs on November 4, 2026: Supabase docs: Auth general configuration; Supabase docs: Auth error codes; Supabase docs: CLI configuration.

Rather hand it over?

Fixed scope, fixed price, paid upfront. The work happens in writing; no call needed.

Supabase Auth errorSupabase: “Signups not allowed for this instance”

Where sign-ups are switched off

Allow new users to sign up is off

The error code is signup_disabled

Local Supabase has enable_signup set to false

Sign-ups were closed on purpose

Rather hand it over?

More on this error

Describe it and get a written quote