How to Fix “Network Protocol Error” in Mozilla Firefox?

Firefox Network Protocol error generally refers to a network protocol violation. It pops up with an error message on your screen referring: “Network protocol error: Firefox has experienced a network protocol violation that cannot be repaired. The page you are trying to view cannot be shown because an error in the network protocol was detected. Please contact the website owners to inform them of this problem.”

Network Protocol Error in Mozilla Firefox
Network Protocol Error in Mozilla Firefox

And as the error states the problem is related to the network issues. Luckily there are fixes that worked for many users to solve the error in their case. So, here in this article, we have listed the most possible solutions shared by our experts to get past the error. But before getting into fixes of this error you must know its occurrence point first. A proper understanding of the cause will help you to select the most effective solution among various in no time.

What Causes “Network Protocol Error” in Firefox?

  • Poor Network Connection– If your network connection is slow or unstable then it won’t allow the website to establish a connection with the server and you might see a network protocol error in Firefox. So, make sure you have a stable and strong network connection to get past such a problem.
  • Corrupted Browser Cache– With time your browser cache gets corrupted and this starts causing a problem when visiting the website or particular page. Moreover, not only the corrupted cache but sometimes overloaded cache on your browser may trigger such a problem. Therefore, it’s been advised to clear your browser cache timely to avoid such problems.           
  • Outdated Version of Browser– Running outdated browsers is most likely to cause various problems like Firefox won’t open, so if you are using an outdated Firefox version then it is possible that you might encounter such a problem. So always make sure to update the browser when being troubled with this problem.
  • Antivirus Software Issues– In most cases, the antivirus software installed on your system can be the major culprit behind such error problems. As it suspects some websites to be harmful or malicious thereby resulting in blocking them from establishing connections so disable the security program temporarily to circumvent the problem.
  • Loads of DNS cache– Apart from your browser cache, loads of your system DNS cache also cause conflict which results in network instability and issues. So, try clearing your system DNS cache to fix the problem.
  • Using Public Network Profile– If your network profile settings have been set as Public, then it might be possible that you may run into this problem. Therefore, it is recommended to set your network profile as Private to avoid getting such problems.
  • Wrong Browser Configuration– If your browser has been wrongly configured or you have changed some settings then you may run into this network protocol error in Mozilla Firefox. So in order to fix the problem try configuring the browser settings properly.

Now as you have taken through most of the possible causes responsible for the problem in question, it’s time to get started with potential solutions to fix it.

Check Your Network Connection

A slow or unstable network connection is most likely to cause such errors. So, it is suggested to check your network connection is running properly before going for any other fixes. However, if you are using a wireless connection then you might not get the ample amount of internet speed which is required to run a browser.

Therefore, it is suggested to plug the Ethernet cable directly into your system. Moreover, connecting through a router might arise internet issues so restart the router and then check for the connection.

Moreover, you can also switch to a different internet connection available or connect using your phone hotspot to check if the error still appears. Connect with your internet service provider to ask them to fix the network-related problem.

Reload Firefox Page

It has been mentioned in many forums by the majority of users that reloading Firefox Mozilla actually fixes the network protocol problem. Before proceeding towards any advanced fixes, reloading the browser is worth giving a try.

You can simply press Ctrl+ Shift+ R or Ctrl+ F5 keys to reload the browser. This will refresh your webpage from the server and not from the Firefox cache thereby solving your issue.

If doing so, doesn’t fix your problem then go for other solutions discussed below.

Refreshing the Mozilla Firefox Browser

Sometimes the internal glitches and bugs start causing various problems. So, refreshing the browser was found to be the proven solution and suggested by users in forums to fix the network protocol issue on Firefox. Simply go for the below steps:

  1. Open Firefox, go for the Options menu and choose the Help option.
  2. Under the Help section tap on the “More Troubleshooting Information” option.
  3. Now go for the “Refresh Firefox” option.
    Refresh Firefox
  4. After that warning prompt window will appear station “Start fresh to fix performance issues”. Accepting it will remove the customizations and extensions excluding important information such as bookmarks and passwords.
  5. Now tap on the “Refresh Firefox” button.
    Refreshing Firefox

Lastly restart Firefox and check for the issue or head to the next fix.

Launch Firefox via Safe Mode

Launching Firefox via safe mode will diagnose the error and probably find a fix for it. Safe mode disables the themes, Add-ons and extensions temporarily that might conflict with the Firefox. To do so just follow the steps below accordingly:

  1. Launch Firefox browser.
  2. Locate the “Options” menu and choose the Help option at the bottom.
  3. Now select the “Restart with Add-ons Disabled” option.
    Restart with Add-ons Disabled
  4. After that go for Restart and then Start in Safe Mode options to launch Mozilla in safe mode.
    Click Start in Safe Mode to Confirm Firefox Safe Mode
  5. Finally, open the web pages and check for the error.

Clear the Corrupted Cache Data

Every time you visit a website the temporary cache gets stored on the browser and after some time this gets corrupted, which later when you visit a website starts conflicting with the website when you visit net time. And if somehow the accumulated cache data on your browser got corrupted then it might end up showing you this error. So, to get rid of the problem you need to clear all the cache data on your browser. To do so follow the steps below:

  1. Open Firefox browser.
  2. Click on the hamburger icon at the top-right.
  3. Go for the Settings option.
    Open Firefox Settings
  4. Now navigate for Privacy and Security over the left pane and click on it.
  5. After that scroll down on the panel and select the ‘Clear Data’ option under “Cookies and Site Data”.
    Cookies and Other Site Data
  6. Now on the appeared window select both “Cookies and Site Data” and “Cached Web Content” and then tap on the Clear option below.
    Clear Cached Images and Files, Cookies and Other Site Data of Chrome

Lastly, close the browser window and relaunch it again. Hopefully this time your webpages will open without showing you a network protocol error.

Flush Your System DNS Cache

As it has already been discussed above that sometimes due to an overloaded DNS cache of your system, you might get troubled with a network protocol error on Firefox. So, it becomes necessary to wipe the DNS cache of your system to fix such kind of problem.

Follow the step guide below to flush the DNS cache:

  1. Open the Run dialogue by pressing the Win+ R keys altogether.
  2. Now Launch Command Prompt in administrative mode by typing cmd on the Run dialogue.
  3. On the cmd panel type the command ipconfig /flushdns and hit Enter.
    Type “ipconfig /flushdns” into the Command Prompt
  4. Now, wait for the cmd panel to complete the operating command request.
  5. Once done with its process, it reflects a message stating: “Windows IP Configuration Successfully flushed the DNS Resolver Cache”.

Finally, restart your system and open the browser to check for the network protocol error.

Update the Mozilla Firefox

Just like other programs and Windows systems the browsers also require updating. So, if you haven’t updated the browser for a while then this starts causing conflict. Using an outdated Firefox version may create such an error. So always make sure to use an updated or latest version of the browser to get rid of this problem. Here are the steps to download the update successfully:

  1. Open Firefox browser.
  2. Click on the hamburger icon at the top-right.
  3. Go for the Settings option.
    Open Firefox Settings
  4. After that scroll down and go for the About Firefox option.
  5. Now click on Check for Updates option.
    Checking for Firefox Updates
  6. Finally, the browser will search automatically for the latest version and download it. Once the download process is done follow the onscreen guide to install the update.

After successful installation restarts your system and launches the Firefox Mozilla to check whether the error is fixed or not.

Switch to Private Network Profile Type

If your Network Profile type is set as “Public” then there is a good chance that you might encounter such a problem. So here it is advised to change the settings to “Private” to fix the Network Protocol error in Mozilla Firefox.

Follow the guidelines mentioned below accordingly to switch from Public to Private:

  1. Go to Settings by pressing Windows + I key on your keyboard
  2. Look for the “Network & Internet” option and tap on it.
    Click on Network & Internet
  3. Now choose the option “Change Connection Properties”.
    Navigating to check Connection Properties
  4. On the appeared window, select the option Private under Network profile.
    Setting Wi-Fi connection to Private
  5. Lastly, restart your system and open the Firefox browser and check whether or not the network protocol error is fixed.

Disabling Antivirus Program/Firewall

Sometimes installed Antivirus programs might restrict the browser to load the requested webpage thereby suspecting it as malicious or harmful. So, you can go for temporarily disable the security software to get past the issue.

Follow the guided steps below to turn them off:

  1. Go to Taskbar.
  2. Locate for “Show Hidden Icons” options on the right side.
  3. Search for your antivirus and right-click on it.
  4. Choose the “Pause Protection” or “Disable Antivirus” option.
    Disabling the Antivirus suite

Note: Options may vary depending on your Antivirus

  1. Click OK on the warning prompt window and close the window.
  2. Lastly, relaunch the browser and check for the issue is resolved or not.

Change the TCP/IP Protocol

In most instances, it has been reported by users that due to the existence of a bug in Microsoft Windows Update, the TCP/IP protocol gets damaged thereby resulting in this error. So, you must reset the TCP/IP protocol to fix such a problem. Here you can follow the below steps to do so”

  1. Go to Command Prompt and launch it as administrator.
  2. Now type the mentioned command netsh int ip reset on the command prompt and hit Enter
    Type netsh int ip reset c:\resetlog.txt in command prompt

Lastly, restart your system and open the browser and look for the problem is solved or not.

Editing the Browser Configuration correctly

It has been recorded in forums that if your browser has been wrongly configured then you may run into this network protocol error in Mozilla Firefox. So, try configuring the browser settings properly to fix the problem.

Follow the below steps:

  1. Open Firefox browser and type about:config in the address bar.
    Accept the Risk and Continue to Open about:config Menu of Firefox
  2. Now tap on the “Accept the Risk and Continue” on the warning page prompted window.
  3. After that on the newly opened window type http.http3.enabled
  4. Then click the toggle button to change the settings to “False”.

Once done relaunch the browser and check whether the issue persists or not.

Reinstall the Browser

It is estimated that after following the above-listed fixes you are able to get past the error. But, if none of the above-mentioned solutions works in this case then try to uninstall the browser and reinstall it again. Follow the steps given below to do so:

  1. Go to the Start or Search box and look for Control Panel.
  2. Once opened locate the “Programs & Features” options and tap on them.
    Opening Programs & Features
  3. And tap on the option “Uninstall a Program” option.
  4. Here look for Firefox and right-click on it and choose Uninstall
    Select Firefox and Click Uninstall
  5. Lastly, download the latest version as guided above and follow the onscreen guide to install it.

So, these are fixes that I hope work for you to solve the Network Protocol error in Mozilla Firefox, try the solutions mentioned one by one, alternatively you can also switch to a different browser like Chrome in an emergency.


Hardeep Kaur

Hardeep is a passionate technical writer with more than 7 years of experience. She has a keen interest in PC games, Windows OS and everything surrounding it. She is a technology enthusiast and fascinated with technology since her childhood days.