> ## Documentation Index
> Fetch the complete documentation index at: https://docs.famulor.io/llms.txt
> Use this file to discover all available pages before exploring further.

# SIP Troubleshooting

> Guide to resolving common SIP integration issues with Famulor

<Warning>
  **Done for you — any region, any country (our EU partner carrier)**

  If you prefer not to configure a SIP trunk or import numbers yourself, our **EU partner carrier** can supply **local numbers in any region and any country**, set up the **SIP trunk**, and **import the connection into Famulor** for you. Provisioning runs **end-to-end through the partner** (carrier-side), so you skip DIY trunk and number import in Famulor.

  * **Custom number region / full-service onboarding:** [Famulor Custom Number Region form](https://tally.so/r/w4bN2Y)
  * **More detail or bespoke options:** [support@famulor.de](mailto:support@famulor.de)
</Warning>

# SIP Troubleshooting

This guide helps you resolve typical SIP integration issues when connecting your SIP provider to the Famulor platform.

## Testing Strategy

1. **Test outbound first** – usually easier and faster to configure
2. **Then test inbound** – once outbound is stable

## Outbound SIP Issues

### Connection Problems

**SIP trunk does not connect for outgoing calls:**

1. **Check SIP credentials** – username, password, and server details
2. **Verify phone-type selection** – select the correct setting with your provider
3. **Fixed IP configuration** – usually enable this and enter the provider’s IP
4. **Verify provider settings** – check codec, transport, and port settings

### SIP Registration

**Important:** The Famulor platform:

* **does NOT send SIP REGISTER** messages to your provider
* **does NOT require incoming SIP REGISTER** from your provider
* **uses direct call authentication**

### Testing Outbound

1. Configure SIP trunk settings
2. Trigger a **direct test call** via the platform
3. Check call logs for error messages

## Inbound SIP Issues

### Setting Up Authentication

**For incoming calls:**

1. Use **IP authentication** instead of username/password
2. Whitelist **all provider IPs** within Famulor
3. **Provider configuration – crucial:**
   * Use **our FQDN** for routing (not the outbound IP)
   * **Send calls to the domain** – ensures proper routing
   * **Do not send to the IP address** – causes routing issues

### Common Inbound Issues

**Calls do not reach the assistant:**

* Verify all provider IPs are whitelisted
* Confirm the provider sends to the FQDN domain (not an IP)
* Check the target number format

## General Issues

**Network:**

* Verify internet connection
* Ensure no firewall is blocking SIP traffic

**Provider Compatibility:**

* Confirm the provider supports direct dialing without registration
* Ensure IP authentication is supported

## Testing Checklist

### Before Contacting Support

1. **Outbound test:**
   * Credentials verified
   * Correct phone-type selected
   * Fixed IP configured with provider IP
   * Direct test call done
2. **Inbound test:**
   * IP authentication configured
   * All provider IPs whitelisted in Famulor
   * Provider sends to FQDN domain (not direct IP)
   * Test call from external number performed
3. **General:**
   * Network connection verified

## FAQ

### Call Transfer Does Not Work

**Question:** Why does the call forwarding feature fail?\
**Answer:** If call transfers fail, try the following steps:

1. **Check SIP transfer settings:**
   * Set transfer mode to “Advanced”
   * Use SIP URI format: `sip:number@sip-server`
   * Example: `sip:+1234567890@sip.provider.com:5060`
2. **Verify provider support:**
   * Confirm your provider supports SIP REFER
   * Check if transfer functionality is enabled on your account
   * Some providers require specific transfer settings
3. **Test different formats:**
   * With port: `sip:+1234567890@sip-server:5060`
   * Without port: `sip:+1234567890@sip-server`
   * Simple format: `sip:+1234567890`
4. **Check the target:**
   * Make sure the target number is reachable
   * Test if the number accepts calls normally
   * Verify the number is not blocked or restricted
5. **Common causes:**
   * Provider does not support SIP REFER
   * Incorrect SIP URI format
   * Network/firewall blocking transfer requests
   * Target number does not answer

**Troubleshooting Steps:**

1. Test with a known working number
2. Try different SIP URI formats
3. Contact the provider to verify SIP REFER support
4. Check call logs for specific error messages

## Getting Help

**When contacting support, please provide:**

* Error messages from the call logs
* SIP trunk configuration
* Test results (outbound and inbound)
* Details of transfer attempts including the SIP URI used

Our team is happy to assist you with setup or troubleshooting: `support@famulor.io`.

<Tip>
  Related pages: [Index](/en/index) and [Support](/en/support), and [FAQ](/en/faq).
</Tip>