10 VoIP Problems: How to Fix Them Forever

December 11, 2019 7 min read

Julie Bai

Julie Bai

Tips to Fix VoIP Issues - Featured Image

If you’re reading this, chances are you’re already an active user of VoIP phones, and you might be having some issues with placing calls over VoIP. Whether it’s choppy conversations, low-quality audio, or any of the other frustrating VoIP problems, we’ve heard them all.
In this guide, we’re diving deep into the top 10 VoIP problems and how you can solve them quickly.
Save your IT person time and get your phones in tip-top shape by finding easy solutions to your most troubling VoIP problems!

Top 10 VoIP Problems

Now, let’s dive into real-world solutions to common VoIP problems that we’ve seen to get you back in action. If you’re strapped for time and can’t read through these VoIP problems, Shy from Nextiva provides a five-minute video breakdown below:

1) Choppy Audio

We’ve all been there. Someone is saying something super important, and it cuts out in the middle of their sentence. We inevitably have to say, “Can you repeat that?” and the person on the other line has to repeat themselves.
This common VoIP problem is likely due to your bandwidth capacity. Bandwidth measures how much data can be sent over a connection in a given amount of time.
If you are hearing someone else cut in and out, it’s a problem with your download bandwidth, and if they hear you cut in and out, it’s a problem with your upload bandwidth.
When using an internet connection, whether it’s for VoIP or browsing, small units of data are sent in packets. When these packets fail to reach their intended destination, packet loss occurs.
The side effects are network disruption, slow service, and low call quality. And, it often impacts high-bandwidth services like audio and video first.

How to fix choppy voice

First, you should verify your network’s stability. Nextiva offers a handy VoIP speed test, enabling you to see how your network performs. There are more testing tools available, but your results will vary. When in doubt, take a sampling of three tests and average them together.
If your bandwidth is lower than what you pay for consistently, you should contact your Internet Service Provider (ISP).

Perform a VoIP Speed Test from Nextiva
Perform a VoIP Speed Test. In this example, the network is perfect for handling thousands of simultaneous VoIP phone calls.

If your network is running slow, you can:

  • Reduce Network Congestion – Whether that’s turning off additional unused phone systems on a network or closing high-capacity applications like YouTube, Netflix, and other streaming services. You can also segment your network with a Virtual LAN (VLAN), so other computers can’t “see” VoIP phones.
  • Prioritize VoIP QoS – If this is a continuous problem, you may want to check your router settings and ensure the Quality of Service (QoS) is set to prioritize VoIP service.

2) Dropped Calls After 11 Minutes

This is a weird VoIP problem that some users may experience. Usually, this problem is reported happening on outbound calls on high-volume networks.
The first culprit is not having the most up-to-date firmware on your device. A quick call to your phone provider should confirm this.
The second issue might be a UDP Timeout, which is the amount of time a UDP route stays open on a firewall or router.
UDP network traffic is faster because it lacks the error-checking capabilities TCP offers. As a result, it’s susceptible to firewalls closing the connection and terminating the call unexpectedly.

How to fix this VoIP problem:

To fix this common VoIP issue, you should adjust router settings to allow for longer UDP timeouts or switch devices to use TCP.
By default, the UDP connection timeout is 30 seconds, and the TCP connection timeout is usually 15 minutes. To increase the connection timeout, you can modify it from the firewall access rules.
You will want first to try increasing the UDP timeout to 60 seconds.
If you’re not already using TCP, you can try switching your devices to use TCP, which is a connection-oriented protocol that specifies the format of data and acknowledgments used in data transfer.

3) Echoes During VoIP Calls

If you’re experiencing echoes on your VoIP calls, there are three potential problems: the device, headset lag, or network latency.
To solve this common VoIP issue, you should test each one, starting with the device itself. Does it have the latest updates? Is everything plugged in properly? Is anything damaged?
Have you done the old trick of unplugging and plugging it back in? Test your calls after you take a look at the device itself. Often, this allows the buffers to empty and can re-sync with the VoIP service of choice.
Depending on the kind of headset you have, you could just have an issue with it. Bluetooth is good, but not perfect. If you can isolate the delays to your headset and not the corded handset, you can fix the issue quickly.
If you’re still experiencing echoes, you may need to improve your network stability.
Related: How Much Data Does VoIP Use? Tips to Forecast Your Bandwidth Needs

4) Unable To Make Calls

If you have a giant “X” on your screen or are unable to make outbound calls, chances are you have two routers that drop certain critical packets of data.
This scenario has less to do with your router configuration but more so with the network layout.
Certain protocols are processed by the Application Layer Gateway (ALG) and rewritten for better flow through a firewall or NAT (Network Address Translation). However, it causes numerous problems for VoIP applications.
To solve this VoIP problem, you will want to disable SIP ALG and ensure you do not have a double NAT or two routers inhibiting your flow of packets. Placing your VoIP phones on a VLAN may also be a solution to this problem, too.

5) Call Connects with No Sound

Hello, can you hear me? If your calls start like this and you can’t seem to hear callers, we’ve got a solution for you!
This usually occurs because a firewall blocks the RTP packets from flowing. The SIP protocol often requires adjustments in routers that rewrite packets using RTP.
To solve, check your firewalls. You may need to open ports as it might not allow flowing traffic to pass.
Related: Is VoIP Reliable? What You Need To Know Before Making the Switch

6) Low-Quality Audio

If you’re experiencing call quality issues, chances are your network’s bandwidth is full, or you have network instability. Audio quality is going to fall back to the most-reliable, lower-bandwidth audio formats not to drop the call.
However, this could be the other party’s VoIP network or the device’s fault.
While you don’t want to go around blaming other people, if you’ve checked out your network bandwidth and stability, you may want to ask them to explore the issue on their side.
If the problem is on your end, you’ll want to ensure your network runs in tip-top shape.

You’ll also want to ensure you have quality network cables for all of your devices. Also, make sure you place your phones on a VLAN to segment them from other network traffic.

7) Calls Go To Voicemail Unexpectedly

It’s a big VoIP call quality problem when your phone doesn’t ring. Whether your inbound calls are going straight to voicemail or even another phone, you’re letting your customers down.
The good news is that it’s a pretty simple fix! A possible setting was likely forgotten, or your phone is no longer registered with the VoIP provider.
You’ll also want to check that your phone is not in Do Not Disturb (DND) mode. You’ll know that this is the problem if a circle has a horizontal line inside it.
Review your current configuration for call forwarding and verify that all of your phones are registered and active.
Related: Business Phone Line Not Working? Here’s How to Fix It

8) Delays In Interoffice Calls

Trying to call a coworker and experiencing latency? Chances are you’re experiencing network congestion.
You can try to reduce internal network congestion, although that may not always be possible. Another option is to use QoS, which might require upgrading to a business-class router that gives higher priority to VoIP data.
The final solution is to ensure you’re using properly terminated cables. Here are some helpful hints on how to ensure you’re following cable termination best practices.
Related: What Is Jitter? The Step-By-Step Guide to VoIP and Network Jitter

9) One Phone Works But Another Doesn’t

If you’ve tested one phone and it isn’t working, but you try another device, and it is, chances are your VoIP Phone MAC address might not be registered.
The other option might be that the configuration itself needs updating.
We recommend testing using a known working location and network port. If one phone works in both places and the other fails, it’s a problem with the phone.
If both phones work successfully at one location, it could suggest that an Ethernet drop is not functioning.
Otherwise, you must contact your VoIP service provider support for possible firmware or configuration updates.
You may need to replace your device if no updates are available and you’re still experiencing this common VoIP issue.
Related: How to Install VoIP Phones (in 5 Easy Steps)

10) VoIP Phone Doesn’t Turn On

Is your phone simply not turning on? You might not be using a Power over Ethernet (PoE) connection. PoE requires the proper network switch and quality wiring.
It’s a pretty simple solution for this VoIP problem. Use a PoE network switch or plug in your AC adapter that’s supplied with the phone. Network administrators seem to indicate that the T568-B wiring pattern is preferred.
Related: 12 Best VoIP Adapters in 2020: Compare Features, Reviews & Costs

Best Practices To Avoid VoIP Problems

We all experience VoIP problems every once in a while. Hopefully, we’ve solved a few of your headaches.
Whether it’s for your current VoIP phone system or a future one, here are a few best practices for long-term success:

  • Segment VoIP phones on your network into their own VLAN for higher performance.
  • Prioritize SIP traffic with QoS. Confirm that your router and switches prioritize VoIP traffic and devices.
  • Use CAT5e/CAT6 cabling with the same media type (10BASE-T vs. 1000BASE-T). Poor wiring causes excess latency.
  • Your ping should be less than 80 milliseconds and your jitter less than 30 milliseconds.
  • Limit phone calls over Wi-Fi whenever possible. Use a dedicated Ethernet line instead.
  • Choose a trustworthy, proven business VoIP provider (like Nextiva!)
See why 100K+ brands trust Nextiva.
99.999% Uptime. Easy to Use. Amazing Service®.
Julie Bai


Julie Bai

Julie Bai was a product manager at Nextiva, UCaaS evangelist, no-bull communicator, and translator for people, dog lover, and mother to an adorably active boy.

Posts from this author
Call badge icon