# Auth error: '500: Database error querying schema'

If you observe the error message `500: Database error querying schema` in your Auth logs, it typically indicates that the Supabase Auth server has encountered `NULL` values in the `auth.users` table where a valid string or empty string is expected.

**Why Does This Happen?**
This issue usually occurs following manual SQL inserts or updates to the `auth.users` table. The Auth service expects specific columns to contain data or an empty string; when it encounters a `NULL` value instead, it triggers a validation error.

**How to Resolve This:**
Identify the column containing the `NULL` values (such as `email`) and execute the following command in the [SQL Editor](https://supabase.com/dashboard/project/_/sql/new) to convert them to empty strings:

```sql
UPDATE auth.users
SET <column_name> = ''
WHERE <column_name> IS NULL;
```

Replace `<column_name>` with the specific column causing the error. To prevent this from recurring, ensure that any future manual modifications to the `auth` schema adhere to the service's requirements.