Why am I receiving SIP response codes 480 or 486?

When routing calls via Voice XML or SIP Trunks, you may encounter error codes in your Call Detail Records (CDRs) or webhook events. Codes `480` and `486` generally indicate transient availability issues on the recipient's telecom side rather than a platform failure.

486 – Busy Here

This response is triggered when the callee's device is actively engaged in another phone call and they do not have call waiting enabled, or they have explicitly rejected your incoming call by pressing the "hang up/reject" button. In SIP terms, the endpoint has returned a Busy Here response safely terminating the sequence.

480 – Temporarily Unavailable

This response occurs when the receiving device cannot be reached. Common scenarios include:

• The user's mobile device is switched off entirely or the battery died.
• The user is outside of their carrier's cellular coverage area.
• The user has placed their device in Airplane mode or "Do Not Disturb" (DND).
• The network operator experienced a routing timeout before the device could answer.

Debugging & Network Blocks

In certain cases where you repeatedly see `480` or `486` against multiple distinct numbers on a specific carrier, it is highly likely that the local network operator's spam filters have temporarily blocked your caller ID mapping. If you suspect this block, please pause dialing attempts for several hours or contact our support team. We can investigate upstream carrier PCAP traces to confirm whether the rejection was user-driven or network-driven.