FreePBX and VX - Call Troubleshooting

Updated by Eric Hufford

Scope

This document outlines some possible causes and solutions to common problems in new or existing FreePBX/VX system installations.

This not a comprehensive troubleshooting guide, but it is a starting point to be used as a reference.

New to the VX ecosystem?
We've made sure you have access to easy-to-understand documentation that is designed to help you get your phone system off the ground. Go here to find your VX product's manual.

Problem: I cannot make inbound or outbound calls

Making a call from an outside phone line into your VX system fails. Calls either don't ring, return a busy signal, or ring and eventually hangup.

FreePBX Causes & Solutions

Possible Causes

Possible Solutions

You don't have a phone service provider

We hate to say it, but sometimes this is the reason. Be sure you have paid access to phone service provider, or your PBX is only going to route calls internally between phones.

Your FreePBX system has not had a Trunk setup to your phone provider

Log into your FreePBX server and create a Trunk connection to your phone provider. Your provider will normally provide the relevant information to do this.

There are no inbound routes created on your FreePBX system

Create inbound routes. These tell FreePBX what to do with a call when it is received.

There are no outbound routes created on your FreePBX system

Create an outbound route to the Trunk you've setup to interface to your phone service provider.

Most installations will only require 1 or 2 outbound routes that all extensions are sent to based on the number that is dialed (i.e.: one outbound route to Provider A for all domestic calls, and another outbound route to Provider B for all international calls)

There are no extensions on your FreePBX system

Create extensions within your PBX. Click here to learn how to do this.

Networking between your PBX and your phone service provider is incorrectly setup

Confirm your PBX and VX are (1) connected together (either directly or via a network) and (2) that they have IP addresses that are different, but on the same subnet (i.e.: 192.168.1.20, and 192.168.1.30)

A firewall is blocking IP communication between your PBX and your phone service provider

This is common with SIP providers that are accessed via public internet.

It is important to ensure that all signaling and media IP addresses are (1) allowed through your corporate firewall, and (2) correctly routed (NAT) to your PBX. Check with your phone service provider for a list of these IP addresses and give them to your IT department.

Incorrect authentication information

There are several ways to authenticate you to your provider. The most widely used on is IP-based authentication. Ensure that your provider has your correct, static IP address if this is the case.

If you are using a username/password authentication, then ensure you (1) have the correct credentials, (2) are registering with the correct IP address or FQDN given to you by your provider, and (3) the registration string you are using to authenticate is what your provider is expecting.

Your provider has changed/added media/signaling addresses

Check with your provider that you have the most up to date list of signaling and media IP addresses

VX Causes & Solutions

Possible Causes

Possible Solutions

The VX is not setup to register to a PBX or managed service provider

Log into the VX and add a SIP server (click on "SIP" on the left-hand side of the web UI). Information on how to do this can be found in your VX manual. Click here for a description of what each field is used for.

There are no extensions setup in the SIP section of the VX, or they are not registering properly

Check the SIP section of the VX and ensure that (1) you have created extensions, (2) they are using the correct username and password, and (3) they are registering with the PBX (click Register).

To confirm extensions are registering with the PBX, click on Information-->Studios--> <studio that is using the extensions> and scroll to the bottom to see the status of each Line/Extension

Extensions are created, but not associated with any Show

Be sure you have a SIP server, a Studio, and a Show created to use the VX. Click here to learn how to build a Show.

Primary DNS is set incorrectly

Check the Primary DNS on the Main page of the VX web UI and ensure that DNS server is accessible and resolves addresses properly.

Problem: The phone rings, but I can't hear anything

Phone rings, but there isn't any audio on one side, the other, or both.

General Causes & Solutions

Possible Causes

Possible Solutions

A firewall is blocking IP communication between your PBX and your phone service provider

This is common with SIP providers that are accessed via public internet.

It is important to ensure that all signaling and media IP addresses are (1) allowed through your corporate firewall, and (2) correcting routed (NAT) to your PBX. Check with your phone service provider for a list of these IP addresses and give them to your IT department.

A firewall within FreePBX has been turned on

If you use the firewall in FreePBX, be sure that you have set the proper zones to Trusted and Internet, and that you are allowing all service provider IP addresses through

Your provider has changed/added media/signaling addresses

Check with your provider that you have the most up to date list of signaling and media IP addresses

There is an audio codec mismatch

Generally, audio codecs are negotiated by devices during a call setup, however, there are times when the correct codec is not used for some reason.

To avoid this, ask your provider to force the use of g.711 and g.722 (alaw & ulaw) codecs, and force the use of these within your PBX as well. At this time, the Telos VX is not compatible with any other audio codecs.

Problem: Call audio is jittery/broken

Calls signal and produce audio, but it doesn't sound clear.

General Causes & Solutions

Possible Causes

Possible Solutions

Network is not properly setup

Ensure you are using managed switches and check that your network switches and routers are prioritizing voice traffic over all other traffic (QoS). Check both local settings on the switch, and other network devices that call traffic flows through

Physical connection or hardware failure

Check all cables, replace if needed. Check external devices and ensure they are not malfunctioning (AdTran units, PRI to SIP gateways, SBC, switches, etc.)

Latency due to connections over public internet

Connections over public internet are subject to harsher conditions, but check with your ISP and/or service provider to ensure that your connection is not experiencing excessive latency or packet drops.

Let us know how we can help

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