> ## Documentation Index
> Fetch the complete documentation index at: https://help.maestra.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Error: "Technical IDs Must Be Unique"

This error appears when Maestra detects an attempt to use a duplicate unique identifier. Re-registering a customer with a unique identifier that already exists in the system is not allowed — each technical ID can belong to only one customer.

## Why this happens

When you import customer data, the error shows up in two scenarios:

<Steps>
  <Step title="Maestra can't determine which customer to update">
    The system can't reliably match the incoming record to an existing customer, so it tries to create a new one. But the technical ID in the incoming record is already taken by another customer, so creation fails.
  </Step>

  <Step title="The customer isn't found by the chosen identifier">
    Maestra falls through to creating a new customer, but the technical ID supplied for that new customer collides with an ID that already exists in the database.
  </Step>
</Steps>

In both cases, the underlying rule is the same: a technical ID is unique across the entire customer database, and Maestra refuses to assign one that is already in use.

## The same rule applies to "account access" contacts

The uniqueness restriction isn't limited to technical IDs. Phone numbers and email addresses flagged as **account access** identifiers follow the same rule — you can't reuse the same phone or email as an account access identifier for two different customers.

<Note>
  If you need to understand how Maestra decides which fields count as unique identifiers and how matching works during import, review the customer identifiers documentation for the full mechanism.
</Note>

## How to fix it

* Confirm which identifier you're sending in the import and check whether it already exists on another customer profile.
* If you intended to update an existing customer, use an identifier that uniquely points to that customer so Maestra can match instead of creating a new record.
* If you intended to create a new customer, generate a technical ID that isn't already in use.
* For account access phones and emails, make sure the value isn't already attached as an account access contact to a different customer.