SIP Integration Issues

This guide helps resolve common SIP integration issues when connecting your SIP provider to VoxLink.ai.

Testing Strategy

1. Test Outbound calls first - easier to configure
2. Test Inbound calls second - after outbound works

Outbound SIP Issues

Connection Problems

SIP trunk not connecting for outbound calls:

1. Verify SIP Credentials - username, password, server details
2. Phone Type Selection - check with provider for correct type
3. Fixed IP Configuration - usually enable and enter provider's IP address
4. Provider Settings - verify codec, transport, port settings

SIP Registration Issues

Important: VoxLink.ai platform:

• Does NOT send SIP REGISTER messages to your provider
• Does NOT require receiving SIP REGISTER from your provider
• Uses direct call authentication instead

Testing Outbound

1. Configure SIP trunk settings
2. Make a direct test call through platform
3. Check call logs for errors

Inbound SIP Issues

Authentication Setup

For inbound calls:

1. Use IP Authentication - instead of username/password
2. Whitelist Provider IPs - add ALL provider IPs in our platform
3. Provider Configuration - IMPORTANT
   • Use our FQDN domain for routing (NOT the outbound IP)
   • Send to domain - ensures correct routing
   • Do NOT send to IP - causes routing issues

Common Inbound Issues

Calls not reaching assistant:

• Verify all provider IPs whitelisted
• Ensure provider sends to FQDN domain (not IP)
• Check destination number format

General Issues

Network problems:

• Check internet connectivity
• Verify no firewall blocking SIP traffic

Provider compatibility:

• Verify provider supports direct calling (no registration)
• Check IP authentication support

Testing Checklist

Before Contacting Support

1. Outbound Test:

   • Credentials verified
   • Phone type selected correctly
   • Fixed IP enabled with provider's IP address
   • Direct test call attempted

2. Inbound Test:

   • IP authentication configured
   • All provider IPs whitelisted in our platform
   • Provider configured to send to FQDN domain (not direct IP)
   • Test call from external number

3. General:

   • Network connectivity verified

FAQ

Transfer Phone Call Not Working

Q: Why is the Transfer Phone Call function not working?

A: If call transfers are failing, try these solutions:

1. Check SIP Transfer Settings:

   • Set transfer call to "Advanced" mode
   • Use SIP URI format: sip:number@sip-server
   • Example: sip:+1234567890@sip.provider.com:5060

2. Verify Provider Support:

   • Confirm your SIP provider supports SIP REFER
   • Check if transfer functionality is enabled on your account
   • Some providers require specific configuration for transfers

3. Test Different Formats:

   • Try with port: sip:+1234567890@sip-server:5060
   • Try without port: sip:+1234567890@sip-server
   • Try simple format: sip:+1234567890

4. Verify Destination:

   • Ensure the target number is reachable
   • Test if the number answers calls normally
   • Check if the number is blocked or restricted

5. Common Issues:

   • Provider doesn't support SIP REFER
   • Incorrect SIP URI format
   • Network/firewall blocking transfer requests
   • Destination number not answering

Troubleshooting steps:

1. Test with a known working number first
2. Try different SIP URI formats
3. Contact your SIP provider to confirm transfer support
4. Check call logs for specific error messages

Getting Help

When contacting support, provide:

• Error messages from call logs
• SIP trunk configuration
• Test results (outbound and inbound)
• Transfer attempt details and SIP URI format used