Diagnosing anonymous or hidden caller IDs in Aircall

This article explains why inbound calls in Aircall sometimes display as "Anonymous," "Unknown," or with no caller ID, and how to identify the cause.

How caller ID works in Aircall

Caller ID (CLI) is carried in the SIP signaling or PSTN metadata sent by the upstream telecom carrier. Aircall displays exactly what the carrier provides and does not generate or modify caller ID. If the upstream provider does not include CLI, Aircall will show the call as anonymous.

Common reasons for anonymous caller ID

Caller has intentionally hidden their number

If a caller has enabled a "hide number" or "private number" setting on their device or carrier account, no CLI is included in the call signaling. Aircall will display the call as anonymous, and this cannot be overridden.

Forwarded calls without CLI pass-through

If your Aircall number receives calls forwarded from another provider, the forwarding carrier may strip or replace the original CLI before it reaches Aircall. This is common in setups where a PBX or third-party carrier sits upstream.

When a call is forwarded and the original caller ID is masked or unavailable, Aircall uses +9084818088 as a placeholder number to ensure the forward completes successfully. If you see this number displayed on an inbound call, it indicates the call was forwarded and the original caller ID was not passed through.

Carrier-level or regulatory restrictions

Some countries or carriers block third-party CLI for regulatory reasons. In these cases, anonymous delivery is mandated and cannot be changed at the Aircall level.

How to diagnose the cause

Steps:

1. Place a direct test call to your Aircall number from a known number. If caller ID displays correctly on direct calls but shows as anonymous on forwarded calls, the issue lies with the forwarding provider, not Aircall.
2. Review multiple inbound calls from different sources. If all calls show as anonymous, a carrier restriction is likely. If only some calls show as anonymous, the individual callers are probably hiding their IDs.

What you can do

Depending on the cause, the options available to you differ:

• Forwarding-related: Contact your forwarding provider and ask whether they support CLI pass-through. If they do, request that it be enabled.
• Regulatory restrictions: No action is available. Some countries require anonymous delivery for forwarded or international calls.
• Caller-driven: No action is available. Aircall cannot override a caller's decision to withhold their number.