Overview
DQE validates phone numbers against official national numbering plans and telecom databases. When a number you consider valid is returned with a negative or unexpected status, it does not necessarily mean the number is wrong — it means DQE could not confirm its validity based on available data.
The most common reasons are explained below.
The country is not activated in your licence
DQE phone validation is scoped by country. Each country must be explicitly activated in your licence before DQE can validate numbers for that country.
If you send a Spanish, Belgian, Togolese, or other international number but that country is not included in your contract, DQE will return a negative or inconclusive result — not because the number is invalid, but because DQE has no authority to validate it.
What to do: Check which countries are active in your licence via My DQE, or contact your DQE account manager to add a country.
The number range was recently assigned by the national regulator
Telecom regulators periodically assign new number ranges to operators. DQE databases are updated regularly, but there may be a short lag between a new range going live and DQE recognising it as valid.
What to do: If you can confirm the number is active and dialable, open a support ticket with the number, the country, and the operator (if known). DQE can fast-track a database update for confirmed cases.
The number is a VoIP, virtual, or non-geographic number
Some numbers — such as virtual mobile numbers, toll-free lines, or VoIP numbers — are technically valid but may be flagged by DQE as non-standard. DQE returns a specific line type for these (e.g. VoIP, Non-geographic) rather than a simple valid/invalid status.
What to do: Check the IdError and Status fields in the DQE response. If the number is being used for customer communication, consider adjusting your validation rules to accept these line types.
The international prefix is missing or incorrectly formatted
DQE expects phone numbers to include the international dialling prefix (e.g. +34 for Spain, +228 for Togo). If a number is sent without the correct prefix, or with a local formatting convention that omits it, DQE may not be able to identify the country and will return an error.
What to do: Ensure your integration sends numbers in E.164 format: +[country code][number], without spaces or dashes. Example: +33612345678 for a French mobile.
What to do if none of the above applies
If the number appears valid, the country is in your licence, the format is correct, and DQE still returns an unexpected result, open a support ticket. See What information should I provide for a phone validation investigation? for the details to include.