unassigned_block

The regulator has not allocated the block the number sits in

The number is well-formed, but the allocation table of its regulator (NANPA, the CNAC, Ofcom) shows its block as free, protected or quarantined: no carrier holds it, so no subscriber can be reached on it.

appears in
reason
credits
Free. Invalid numbers never cost a credit.

What it means

Where a regulator publishes its number-block allocations, Spaw reads the block a number sits in. A geographic number missing from a fresh copy of a complete table (NANPA for the United States and its territories, the CNAC for Canada), or listed by Ofcom as free, protected, quarantined or reserved, has no holder: the plan allows the shape, but nobody can be reached there today.

Unlike the other reasons, the answer keeps the parsed number: e164, the display formats, the country facts and block_status "unassigned" are all filled in, and the table that decided it is named in sources. The inference from an absent block is withheld when the table is older than 45 days, so a code assigned since the last sync is never called free.

What to do

Reject it at signup like any invalid number; the block cannot ring. If you believe the number is in service, the version in sources says which copy of the table answered, and the regulator publishes the current one.

Example response

{
    "valid": false,
    "reason": "unassigned_block",
    "e164": "+442079460018",
    "country": "GB",
    "block_status": "unassigned",
    "risk_score": null
}

Abbreviated: a real answer carries all 33 fields, listed in the validate-phone reference.

Related

markdown version: /docs/reasons/unassigned_block.md