# 'Scan error on column confirmation_token: converting NULL to string is unsupported' during Auth login

If you encounter an HTTP 500 error during authentication with the message `error finding user: sql: Scan error on column "confirmation_token": converting NULL to string is unsupported`, this typically indicates that the GoTrue Auth service found a `NULL` value in the `auth.users.confirmation_token` column, where a non-nullable string is expected.

To resolve this, update the `confirmation_token` to an empty string where it is `NULL`. You can execute the following SQL query in the [SQL Editor](https://supabase.com/dashboard/project/_/sql/new):

```sql
update auth.users set confirmation_token = '' where confirmation_token is null;
```