---
page_type: error
code: 32105
message: "32105: SIP: Invalid contact header"
level: WARNING
product: Programmable Voice
---

Possible loop in Contact header

**Possible Causes**

You're sending `127.0.0.1` or `localhost` in the Contact header which will create a loop at Twilio.

**Possible Solutions**

Configure your SIP stack so it populates the Contact header properly.