# unable_to_create_user (/docs/reference/errors/unable_to_create_user)

The user could not be created during authentication.



## What is it? [#what-is-it]

This error occurs when Better Auth fails to create a new user during the authentication process. It typically happens during OAuth or SSO-based signup flows when a new user record is expected to be created but the operation fails.

## Common Causes [#common-causes]

* Database write failure due to connection issues, timeouts, or transaction errors.
* Missing or invalid required fields in the user schema.
* Unique constraint violations (e.g., email already exists).
* Mismatch between your database schema and the expected Better Auth schema.
* Errors thrown inside custom database hooks (e.g., `user.create`).
* Misconfigured adapters or database clients.

## How to resolve [#how-to-resolve]

### Verify database connectivity [#verify-database-connectivity]

* Ensure your database is reachable and properly configured.
* Check for connection pool issues, timeouts, or failed queries.

### Validate schema and constraints [#validate-schema-and-constraints]

* Make sure all required user fields are present and correctly typed.
* Check for unique constraints (e.g., email conflicts).

### Run migrations [#run-migrations]

* Ensure your database schema is up to date with the current Better Auth version.

### Review custom hooks [#review-custom-hooks]

* If you are using `databaseHooks.user.create`, ensure it is not throwing errors or returning invalid data.

### Inspect logs [#inspect-logs]

* Check server logs for detailed error messages during user creation.