Why are the caller IDs of the incoming notifications I receive incorrect?

Question

Sometimes I receive notifications from a different number than I'm expecting — is there a reason why this is happening?

Environment

• All versions of xMatters

Answer

When xMatters generates a call, Caller IDs are passed from our provider to their downstream carriers. All xMatters calls submit the Caller ID using standard formatting, either from the system-level Caller ID or from any configured override.

However, for international calls, different carriers vary in their preferred caller ID formatting. Since calls may traverse several networks before reaching their destination, the caller ID information may be altered, replaced, or reformatted along the way.

There are three main circumstances that cause a caller ID to be displayed incorrectly:

1. A caller ID may be modified along the way by intermediary carriers or by the recipient's carrier, including when calls are routed over different networks for mobile versus landline devices.

2. The caller ID may be lost or replaced when crossing international borders, or when a North American caller ID is delivered to overseas carriers that apply their own numbering rules.

3. Local regulations or carrier-level spam and fraud prevention policies sometimes dictate that a caller ID be modified or replaced.