## TL;DR

Assignment rules evaluate in order and stop at the first match, so a lead that matches nothing (or matches an early catch-all) lands on the default owner with no error. Test the rule entries against a real lead, check the order, and confirm the web-to-lead or API call actually requested assignment.

## Error

```text
(No error; the symptom is leads owned by the default owner or a queue nobody watches.)
```

## Steps

1. Confirm the insert requested assignment: API inserts need the assignment rule header or checkbox set, or rules never run. Expected: you verify assignment was even attempted.
2. In Setup, open the lead assignment rules and read the entries top to bottom. Expected: you see the order and the criteria of each.
3. Take one misassigned lead and evaluate it against each entry in order. Expected: you find the entry it hit (often a too-broad early rule) or confirm it hit none.
4. Fix the order (specific rules before catch-alls) and tighten criteria. Expected: the test lead now matches the intended rule.
5. Set a monitored default owner, not a dead queue. Expected: unmatched leads still land somewhere visible.

## When to use

- Leads arrive with the wrong owner or the default owner.
- Web-to-lead or API-created leads never get assigned.
- After reorganizing territories or teams.

## When not to use

- Flow or Apex-based assignment (different engine).
- Owner changes blocked by sharing (different error).

## Tool compatibility

- Salesforce lead assignment rules; web-to-lead and API inserts.
- The assignment rule header on API calls.

## Variant phrasings

### leads not assigned on create

Assignment was never triggered; check the header or checkbox.

### assignment rule skipped

An early rule matched first; check the order.

## Why it happens

Rules stop at the first match and fail open to the default owner. There is no "no rule matched" alert, so misconfiguration looks like the rules doing nothing.

## Edge cases

- API inserts default to not running assignment rules; the header must opt in.
- Inactive users in rule entries silently skip; audit entries after deactivations.
- Case assignment rules are separate; lead rules never affect cases.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_KMLoWLWVp6hdEnN7gMUKlg