5 Common VoIP Problems and How to Fix Them

VIRTUAL PHONE Apr 19 2021 / 6 min read

The shift from desk phones to VoIP is happening. In the face of remote working, technologies like VoIP have helped businesses to carry on with a sense of normalcy. Offering unlimited calling, SMS and conference calling at a much lower price, it’s no wonder so many businesses have made the switch. However, the process hasn’t always hassle-free. You might be experiencing some common issues. Not to worry – our technical support team has collated some common issues that customers call in for and have provided some quick fixes!

Choppy/broken audio

This is a common issue that many people using VoIP experience at least once. It includes you not being able to hear the callee and vice versa, where the audio might completely disappear for a few seconds or cut in the middle of conversations.

The first step is to identify when this problem is occurring. You should figure out whether it’s coming from your end or the callee.

How to fix this problem

Run a speed test.

Poor internet connection is one of the main reasons for choppy audio, and so a speed test will tell you if this is a problem on your end. The recommended speed depends on whether you are making a call or video conferencing. You can run a speed test using websites like or

If speed is an issue:

  • Move your device closer to the router.
  • Check if a wired connection is still showing low speeds. If not, consider using that. If the speed is high, but you are still experiencing audio problems, try upgrading your Ethernet cable to a Category 5 cable, which should fix the problem.
  • Try a wired connection. It is much more stable than WiFi and will often give you the highest speed your broadband offers. Ethernet cables are inexpensive, so this is an easy fix. However, if you are still getting low speeds on a wired connection, you should contact your broadband provider.
  • Use a WiFi extender to increase your WiFi signal's strength if your room is too far from the router. You can purchase them from your provider, or get them off Amazon. They are relatively easy to configure and will extend the router coverage to blackspots.
  • Close other applications that are taking up bandwidth. This includes streaming sites, like Netflix or other applications you might have open on your laptop.
  • Avoid other activities that take up bandwidth. This includes large downloads or uploads or large-scale syncing (like to iCloud or Google Photos) in the background.

Check your headphones.

It can be your headphones that aren’t working correctly, so it’s always best to test the audio through them and another speaker or headset.

Audio echo

You might experience echoing when you are hearing your own voice while talking. This issue can be a result of your telecom provider’s servers being too far away.

How to fix this problem

  • Check your VoIP system. Damaged wiring can cause echoing. Ensure that there is no physical damage and that everything is plugged in correctly and securely. Contact customer support if something is faulty so that it can be replaced.
  • Move your VoIP device. Electromagnetic interference can be a result of electrical devices being placed too close to each other. It can cause echoing and lag. Make sure the router, computer and VoIP device are installed far apart to avoid interference.
  • Check if your headset volume is the cause. Headphones can cause echoing, and the simple way to check is to lower the volume and see if the problem stops.

Audio delays and jitter

VoIP works by sending voice data via packets through the internet. Jitter is when these packets are dropped or sent in the wrong order, leading to missing or mixed-up audio.

How to fix this problem

  • Use a jitter buffer. A jitter buffer makes sure that the voice packets are stored and sent to your network in evenly spaced intervals to ensure clear voice quality. Your VoIP provider can help you with this.
  • Reconfigure your software firewall settings. You can enable Cut-Through Forwarding (CTF) or NAT acceleration to speed up network performance. However, you will only see a noticeable difference with this if your internet speed is pretty high (above 100mb/sec).
  • Enable Quality of Service (QoS). You can set QoS to prioritize VoIP traffic, known as DSCP class 46, which will tell the router to prioritize voice packets instead of other data packets. Whether you can enable QoS depends on your broadband provider, so check if your provider allows this first.

Dropped voice calls

You could be experiencing dropped calls for multiple reasons, and if it’s a consistent problem only affecting you on your end, it could be a result of numerous factors.

How to fix this problem

  • Check your internet connection. Again, run a speed test and make sure that your speed is stable. If you use eFone, the app will tell you on the call screen if your connection is weak. Try switching from data to WiFi and vice versa to test if it’s a connection problem.
  • Call duration limits for group calls. Your provider could have limits on call durations, especially on conference and group calls. Check your account or plan to see if this is the case.
  • Check safeguard duration limits. Many providers and carriers set up limits to prevent calls from running unintentionally for hours. This could be 120 or 180 minutes. If you have previously made calls longer than this, you should raise the issue with your provider. Otherwise, the best thing to do is to start a new call.

Failed calls/calls not connecting

By failed calls or calls not connecting, we’re referring to problems like:

  • Getting a busy signal every time you call
  • The call dropping after a few seconds
  • The call disconnecting after a certain period of time (such as one hour)

How to fix this problem

  • Check the area code. Make sure you are using the correct area code for the number you are dialing. Not including the area code can result in failed calls or wrong numbers.
  • Check your plan. Most providers offer several plans. Your plan might not include international calls or calls to the country to which you are calling. You could also be out of minutes. Check to see if this is the case.
  • Unblock your caller ID. You can usually block your number on outgoing calls with most VoIP providers. However, many businesses block incoming calls from blocked numbers. Turn your caller ID on and try again.
  • Restart your phone or modem. It might seem like an obvious trick, but sometimes we forget the obvious. Give this a try and see if it helps.

If you are still having trouble making outgoing calls, you should contact your VoIP provider to determine the reason.

Pro-tip: disable SIP ALG

SIP ALG is not a problem in itself, but it should be disabled as it’s poorly implemented in most routers. It’s meant to inspect and modify VoIP data packets and prevent firewall problems. However, in many cases, it corrupts data packets to make them unreadable and ends up being a problem for most people.

Problems caused by SIP ALG

  • One-way audio
  • Failing to make calls
  • Call quality fluctuating
  • Losing connection during a call
  • Audio delays or jitter

How to disable it

You can disable it by accessing your router settings. Every router is different, so a quick google search will tell you where you need to go to disable it. If you are still having trouble, you can contact your provider to ask them how to do it.


Sohah Ahmed

Marketing Manager
30 Day Free Trial