How to Diagnose the Most Common VoIP Connectivity Problems? - Wiki

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How to Diagnose the Most Common VoIP Connectivity Problems?

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The quality of internet connection has drastically improved over the last decade. It has become more robust than ever and thanks to that connectivity failures might be less common; however, they can still happen unannounced at any time.

Since Voice over Internet Protocol (VoIP) relies completely on the internet connections to function, getting yourself acquainted with the most common VoIP connectivity problems can help resolve some of the easier connection issues that the business might experience.

In this article, we will discuss how to diagnose some of the most common VoIP connectivity problems.

How to Diagnose the Most Common VoIP Connectivity Problems?

Many modern-day businesses rely on business VoIP solutions as the primary source of communication to consumers. Moreover, these businesses use the VoIP networks for internal communication as well. Therefore, it becomes imperative to ensure that the system never fails, but when it does, the organization can have the communication system up and running as soon as possible.

The following are some of the most common VoIP connectivity problems and how you can resolve them as quickly as possible.

Problem 1 – Registration/Connection problems

Registration problems occur when the SIP/IAX client is unable to connect with the server thus is unable to make and receive calls.

You can easily identify this problem in your portal if you see the status “No registration found”.

If you find yourself unable to use the phone and notice the mentioned status on your portal, try the following to determine what is causing the registration problem and how to fix it:

1.1 Check the network LAN connection.

Verify the status of the device. Most devices will tell they are having a connection problem by the color of the LED lights on it. An amber light on the phone/line LED is the most common sign for this so, if that is the case verify the device is properly connected to the network. Make sure to check all endpoints.

Check if there are intermediary devices like a switch or internet outlet on the wall and try overpassing them by connecting the SIP/IAX device directly to the internet router in order to verify if one of those connections is the root of the issue. If the registration is restored by doing that, then that connection would need to be checked and fixed.


1.2 WAN connectivity.

If all your connections are okay and the device is properly connected to your network, the next step is confirming that you can reach the server you are using. For this, you can simply perform a ping from your PC or Mac to see if you get response from the server. You can find instructions about how to perform a ping, here: What is a Ping? - Wiki

If the ping does not work, try pinging a few more servers to see if the problem is that specific server. A failed ping could mean your firewall or network is blocking the communication.

It is also possible that for any given reason your WAN IP address got blocked by the VoIP provider. To confirm if this is the problem you can email the support team your public IP address to [email protected] explaining that you do not get response from the servers, and they will gladly confirm if it is blocked or not.

1.3 Verify the configuration.

Make sure you are using the configuration recommended by for your device. You can check our configuration samples to confirm: Devices - WIKI

Although the configuration samples have the most recommended configuration and that has been reported by other users as the best, please note you can still try changing some settings like the port and the transport type in use to see if any of these specific parameters are causing the problem.

Please note that supports the ports 5060, 5080 and 42872 so, you can always test using an alternative port. On some occasions the registration fails because the port set is blocked or congested so using an alternative one may fix it. The same may happen with the transport type; supports UDP and TCP so you may try using one or the other to verify the problem is not caused due to problems with the UDP or TCP traffic in the network.

Additionally, you may try using the server’s IP address instead of the domain name to discard a DNS problem. E.g., instead of set in the configuration

You can find more information about registration problems in the Wiki, here: Registration issue - Wiki

Problem 2 – Phone and Voice Quality

If the LAN and networking equipment are working with no issues, start looking for other reasons behind the VoIP connectivity problems. If you are experiencing phone and voice quality issues, it becomes crucial to rule out different reasons such as latency, interference, call volume, and faulty phone equipment.

The following are some of the ways through which you can check out your VoIP voice quality.

2.1 Move the router to a different position.

If there is any phone or voice quality connectivity issue, try to keep the router away from the system, power strips, and fans. All these things can cause interference by being too close to the router.


2.2 Check for any intermediary equipment.

Bypass devices or splitters that are connected to the phone or the router. It means that plug the router and the phone directly into each other and remove any other third-party equipment. If the issue gets resolved, it is likely that the other connected device is faulty.

2.3 Inspect the connected wires.

While you are checking for potential issues hindering with your phone and voice quality, also make sure that you inspect all the connected wires. Ensure that all cables and wires are dry and are not too long. Wires that are too long can cause voice quality issues.

2.4 Check out old equipment.

If you have been using specific equipment such as a microphone, headset, or the phone itself for a long time, it might need an upgrade soon. There is a possibility that your old equipment is resulting in poor voice quality.

2.5 Run a speed test.

First and foremost, run a bandwidth speed test. The speed of the internet will determine the number of VoIP phones your network can handle. However, before you run the bandwidth speed test, do ensure that your system is plugged directly into the modem.

2.6 Verify you are using the best server for your location.

Poor audio quality could be caused by high latency and one of the most common reasons for this is that you are not using a server with good latency for your location. To discard this as the reason of the problem you can test using a different server.

Please note has servers all over the USA and Canada, some in Europe and in Australia. Make sure to pick one near to your location and ping them to see which one gives the best latency.

You can find a list with all the servers available, here: Choosing Server - Wiki

2.7 Look for packet loss.

Packet loss is the situation wherein data packets are correctly transmitted from one end, however, they fail to reach their intended destination. Such a situation usually arises because of bad network conditions as well as internet congestion.

Because VoIP connectivity is based on data packet transmission, even a small amount of data packet loss can result in connectivity issues. To diagnose if you are facing a packet loss issue, you will have to run a ping test. While you run the ping test, make sure you also document the results to give them to the ISP, if necessary.

2.8 Check your network configuration.

Call quality problems may happen because the configuration of your network is not suitable for VoIP.

It is recommended that SIP ALG is disabled on the configuration of the internet router of the network. This is common and usually enabled by default on most routers, however, it is known for causing troubles with SIP traffic.

Check your network/firewalls allows traffic through the port range 10000-20000. This is the range uses for the RTP traffic. In other words, the audio is streamed through this port range.

You can refer to this article to confirm what parameters need to be allowed in your network/firewall: Firewall - Wiki

You can find more information about call quality problems in the Wiki, here: Call quality issues - Wiki

Problem 3 – Security

Because VoIP makes use of internet services, it is also susceptible to security threats. Of course, security threats can affect connectivity and call quality. In addition to that, it can also place customer data at risk. Therefore, if you believe the connectivity problem is because of security threats, you must ensure that any of such issues are addressed immediately.

Some of the different ways through which you can address connectivity issues arising due to security are as follows.


3.1 Reset passwords.

Whenever you feel that connectivity issues are arising due to security threats, immediately reset your password. Moreover, ensure that you are using strong passwords which include both uppercase as well as lowercase letters along with numbers and symbols.

3.2 Set firewalls

To enhance the security of your VoIP devices, ensure that you implement a firewall for your VoIP systems. Using the firewall will limit the kind of traffic allowed on calls. Moreover, it will also help in mapping unusual patterns for better security.

Final Thoughts

While the reliability of VoIP systems has increased significantly over the last decade, connectivity issues can arise anytime. Therefore, before you get in touch with your VoIP service provider, try to look out for the above-discussed common problems. If you can resolve the issue on your own, it will help you get the systems back up immediately.

If none of the recommendations help with your problem or if you think that the issue is out of your control, contact support team via chat or email them at [email protected]


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