Easy VoIP Troubleshooting Tips for Common Connection Issues

April 4, 2019 9 min read

Gaetano DiNardi

Gaetano DiNardi

VoIP Troubleshooting - Solve common VoIP connection issues

Nobody likes waiting to speak with a support agent when they’re dealing with technical issues like, say, network jitter. From the automated routing messages to the random disconnections, it’s likely not something you look forward to.
That’s why it can be helpful to know some basic steps to take when your VoIP phone is experiencing issues. Troubleshooting first allows you to cut some potential problems early on. Even before having to reach out to a tech support representative.’
Here, we’ll cover five of the most fundamental issues that can occur with any cloud phone system.

Troubleshooting 5 Common VoIP Issues

VoIP problems can involve networking or Internet connectivity issues. They can also include security problems and issues involving related devices. Follow these steps in order and use the process of elimination to determine which issue needs fixing.

No time to read? Shy from Nextiva breaks down these common VoIP problems in the video below:

Problem #1: Networking and LAN Issues

illustrated man frustrated with computer

Common Symptoms: Cannot make calls, one-way audio, choppy voice, bandwidth issues, router issues
Networking and Local Area Network (LAN) issues usually involve problems between personal computers or the equipment that connects them to the internet. This is often a router issue. Either the router is malfunctioning, or you have the wrong router for cloud telephony.
When using VoIP, you’ll need a router that prioritizes calls through the internet. This feature is known as Quality of Service, or QoS for short. This prioritizes VoIP calls ahead of less-critical network traffic. Most modern broadband routers offer this feature. You may experience call quality issues if you don’t set it up.
How to make sure your LAN is working properly:

  1. Unplug power to the router. Wait 30 seconds. Plug the cord back in.
  2. Set up QoS settings for VoIP.
  3. Disable SIP ALG or forward ports
  4. Check for firmware updates for your router.

1) Reset your router and all computers and check the wiring

This may seem obvious, but the first thing you should check is your equipment’s wiring. Ensure all hardware is plugged in correctly.
Next, unplug all power cords, leave them out for 30 seconds and then plug them back in. Wait for all the lights to turn back on. This will give your router and networking equipment a fresh start and clear any basic issues they may be experiencing.

2) Ensure you have a router configured for VoIP prioritization

This means checking if your router supports VoIP QoS (Quality of Service) settings. Confirm they’re enabled. While every router is different, most QoS settings are in the router’s management interface.

3) Try disabling SIP ALG

Most consumer routers offer a “feature” that attempts to fix VoIP issues. Trust us; it causes more problems than it’s worth. The Application Layer Gateway (ALG) modifies packets sent between internal devices. The quick fix here is to turn off SIP ALG and disable any “SIP Helpers” within your router. Follow this guide to learn how to disable SIP ALG. When troubleshooting this VoIP connection issue, calls dropping after 10 minutes and device registration issues are common symptoms.
If your router doesn’t have a VoIP-tuned QoS feature, you may need to dedicate more bandwidth to your VoIP devices. Some routers let you dedicate a minimum of 100 Kbps to a MAC address. It’s crude, but it works. To do this, you’ll need to know the hardware address of your phone. It’s usually found on the back of your phone or by navigating the phone’s on-screen menu.

4) Upgrade your router

If reconfiguring your router settings doesn’t work, and you’re still experiencing router issues, you may need a new router. Upgrading to a dual-band router can significantly improve your VoIP experience. If your vendor no longer supports your router, look into an open-source firmware such as DD-WRT or FreshTomato.
Dual-band routers are capable of transmitting on different frequencies. This way, users can assign each frequency a different task. Your 2 GHz network can handle your thermostats, guest traffic, and not your real-time communication devices. Your 5 GHz network is ideal for TVs, IP phones, conference phones, workstations, etc. You can assign VoIP communication a dedicated channel.
Also, we updated our VoIP router buyer’s guide. Get the best VoIP router from this list!

Problem #2: Phone and Voice Quality

Illustrated lady on the phone

Common Symptoms: Echo, bad audio, buzzing, delays in transmission
If you’re sure all your networking equipment is working correctly, you can look into other reasons why your VoIP service isn’t functioning properly.
If you’re experiencing phone and voice quality issues, it’s important to rule out reasons such as call volume, interference, and faulty phone equipment.
Here’s how to check your voice quality:

  1. Cover your phone’s mouthpiece. If the echo, buzzing or interference stops you may just need to turn down the volume of your earpiece or speakers.
  2. Move your router. Keep the router away from your computer monitor, fans, and power strips. They could be causing interference by being too close.
  3. Check any intermediary equipment. Bypass any splitters or caller ID devices connected to your router and phone. This means to take any third-party equipment out of the equation by plugging the router and phone directly into one another. If the problem ceases after you bypass a certain piece of equipment, it’s likely that piece of equipment is faulty.
  4. Inspect your wires. Ensure that all wires and cables are dry and that they aren’t too long. A wire that’s too long can cause voice quality issues
  5. Check for old equipment. If you’ve had certain equipment like a headset, microphone or the phone itself for a long time, it may need an upgrade. Old equipment can sometimes result in poor voice quality.

Related: Business Phone Line Not Working? Here’s How to Fix it

Problem #3: WAN and Internet Connectivity

illustrated person having connectivity issues

Common Symptoms: Choppy voice, voice delays or echo, speed issues, number not found or busy signal
Another common set of problems that can cause an array of issues is wide area network (WAN) or internet connectivity issues. These include issues that aren’t necessarily contained within your vicinity or equipment. This includes trouble with your Internet Service Provider (ISP).
Some internet bundles are for web surfing and streaming but aren’t powerful enough to use VoIP. Transporting voice packets is essential for VoIP calling.
It requires an additional set of internet protocols that your ISP may not be providing. Before you begin VoIP troubleshooting, ensure you have a business-class internet bundle that supports VoIP usage.
How to check your WAN connectivity and internet speeds:

  1. Run a bandwidth speed test
  2. Test for packet loss
  3. Contact your ISP

1) Run a bandwidth-speed test

Nextiva has an easy-to-use speed test to determine if your network is VoIP-compatible. Your speed will determine how many VoIP phones your network can handle.
Before performing the test, ensure you plug your computer directly into the modem.

2) Test for packet loss

Packet loss is a condition where data packets are transmitted correctly from one end of a connection, but fail to make it to their intended destination.
This is usually caused by bad network conditions or internet congestion. VoIP connections are dependent upon data packet transmission.
Therefore, even a small amount of packet loss can result in VoIP communication issues. To find out if you’re experiencing packet loss you’ll need to run a ping test. You can learn all about how to run a ping test here.

ping test results
Source: WikiHow

As you run the tests, document your results so you can give them to your internet service provider if necessary.

3) Contact your ISP

If you’ve looked at your LAN, connectivity and equipment and determined that the issue is with your WAN, you’ll likely need to call your ISP. They can help you determine if there’s an outage in your area or help you troubleshoot your internet connectivity issues.

Problem #4: Security

Illustrated man having security issues

Common Symptoms:VoIP deregistration, firewall issues
Since VoIP is connected to the internet, it’s susceptible to virtual attackers and security threats. Security issues can not only affect call quality but also places your customer data at risk.
That’s why if you suspect you’re having issues with VoIP security, you should address them immediately.

  1. Reset your passwords
  2. Identify rogue devices
  3. Implement VLAN tagging

1) Reset your passwords

Credentials for VoIP services can be hacked. They’re in high demand. With your SIP/VoIP credentials, unauthorized users can place expensive calls, or even listen to calls in progress. If you suspect your password has been compromised, reset all passwords. Additionally, consider updating passwords on a regular basis.

VoIP Troubleshooting: LastPass Dashboard Screenshot
Source: LastPass

Use strong passwords that contain letters (both capital and lowercase), numbers and symbols. It’s smart to encrypt these passwords somewhere safe using a password encryption software like LastPass.

2) Set security layers and firewalls

It’s possible for the VoIP admin to deploy a firewall for your VoIP systems. These firewalls usually function by limiting the type of traffic allowed on the calls and closing the session once a call concludes.
There are also firewalls that help map unusual patterns and identify signs of an attack. While many VoIP routers have these capabilities, talk to your VoIP provider about their security measures offered.

Problem #5: Faxing Issues & Other Devices

Illustrated businesslady trying to send a fax

Common Symptoms: Faxing errors, alarm system integration
In the digital age, enterprises rely more and more on digital paperwork for the business. However, sometimes fax machines, printers, and scanners are still used to send and receive data. Fax machines, unfortunately, aren’t compatible with VoIP. This could lead to problems for those who rely on these machines to send information.
How to combat issues because of third-party equipment:

  1. Install compatibility components
  2. Find a compatible security solutions

1) Install compatibility components

It’s unlikely you’ll be able to plug your fax machine into your VoIP equipment. You’ll probably need to install compatibility equipment to run a fax machine and other similar devices through your VoIP phone.
Equipment varies among providers. But many will offer bridging components (like a fax bridge) to help you send and receive digital information.

2) Find a compatible security system

Many security systems require an internet connection these days. However, you’ll want to ensure yours is compatible with your VoIP phone service.
If the security system isn’t compatible, it can cause issues with both the security system itself and your VoIP service. You may need to check with your VoIP service provider about compatibility with certain security systems, but you can learn more about how alarms work with VoIP.

Two Scenarios Where You Must Call for Help

If you hit a dead end with the above issues, it may be time to call for help. Since VoIP calling relies on internet service and internet phone service providers, sometimes the problem is simply out of your hands.

Your internet is down

If your internet is down or you’re having connectivity issues when trying to surf the web, send an email, or watch videos, you’ll have to contact your ISP. If you are unable to connect to the internet, there is no way for your VoIP service to work, so you must fix this issue first.

You have call connectivity issues

Also, if you notice issues with your VoIP equipment or call connectivity, it’s better to call your VoIP service provider. They can help you troubleshoot any issues as an expert. However, most VoIP connection issues can be covered here.
VoIP troubleshooting is a great way to diagnose common VoIP issues on your own without contacting your internet or VoIP providers. Proper troubleshooting lets you determine where the problem is, what’s causing it, and how to fix it. It’ll also save you money in replacing otherwise-functional network routers and switches.
After you’ve checked all your cables and power cycled all your equipment with no success, your VoIP provider may need to perform more advanced troubleshooting.
This is why it’s important to work with a trusted VoIP leader that is known for superior reliability. If you work with a knowledgeable and trustworthy company, you should be up and running in no time.
Related: How Network Jitter Affects Your VoIP Calls (& How to Fix It)

Gaetano DiNardi


Gaetano DiNardi

Gaetano DiNardi led demand generation at Nextiva and has a track record of success working with brands like Major League Baseball, Pipedrive, Sales Hacker, and Outreach.io. Outside of marketing, Gaetano is an accomplished music producer and songwriter. He’s worked with major artists like Fat Joe, Shaggy, and loves making music to stay turbocharged.

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