Unable To Create User

UNABLE_TO_CREATE_USER occurs when a flow needs a new user row but the adapter or schema rejects the write. It most often appears during sign-up, first social sign-in, SSO just-in-time provisioning, or SCIM-created accounts.

Response shape

{
  "code": "UNABLE_TO_CREATE_USER",
  "message": "Unable to create user",
  "status": 500
}

Common causes

• Database migrations are missing or stale.
• Required user fields are missing.
• Email unique constraint conflicts with an existing user.
• A custom user hook returned invalid data.
• The adapter lost a transaction during user plus account creation.
• The database connection failed or timed out.
• Imported data violates the current schema.

How to fix

• Confirm the user table or collection matches the resolved Kernia schema.
• Check whether the email already belongs to another user.
• Validate custom hooks and imported profile data.
• Run the same flow against the adapter test suite.
• Inspect database logs for constraint or type errors.

Account linking

For OAuth and SSO, do not resolve this by blindly linking on email. Link on provider account id when possible and require verified email before any email-based linking policy.

Tests

Tests should cover duplicate email, missing required field, hook failure, adapter failure, and successful rollback when account creation fails after user creation.