- Firefox is reliable and fast browser that maintained a steady market share over the years despite the wave of new browsers entering the market.
- The browser is fully compatible with Windows 10 and you can even use it as your default browser.
- If Firefox notified you it can't find particular websites, use this guide to fix the issue. This guide is part of our Firefox troubleshooting section.
- Interested in optimizing your browsing experience on Windows 10? We're sure you'll find great value in this collection of guides.
However, in spite of a myriad of upgrades, Firefox is far from flawless. Some users experienced the Hmm. We’re having trouble finding that site error which, seemingly, occurs frequently.
If you’re seeing this error on a regular basis, make sure to check the solutions we enlisted below.
What to do if Firefox can’t websites
1: Check your connection
First things first. We need to make sure that the Firefox browser is the one to blame for the error. Open an alternative browser and try connecting. If you’re having better luck, than move to the additional steps below.
Otherwise, if you’re still unable to open any website on the alternative browser, too, — we have the connection issues at hand.
Now, these are always difficult to deal with due to a variety of possible reasons why the network is down.
Maybe it’s on your side or maybe is the ISP. Either way, we suggest you take these steps in the order they’re presented and look for resolution:
- Try using the wired connection instead of the wireless.
- Restart your router/modem and PC.
- Flush DNS:
- Press Windows key + S to summon the Search bar.
- Type cmd, right-click Command prompt and run it as an administrator.
- In the command line, type the following commands and press Enter after each:
- ipconfig /release
- ipconfig /renew
- After the process ends, type in this command and press Enter:
- Close the Command Prompt.
- Run the dedicated Troubleshooter:
- Temporarily disable the VPN/Proxy.
- Update router’s firmware.
- Reset router to factory settings.
2: Clear Firefox’s cache
Firefox, as any other browser does, collects a lot of cached data. Besides the browsing history, it’ll collect cookies which store the website data.
The intention here is to speed up your surfing experience, but cookies can, when pilled up, cause issues within the browser. What we recommend doing is clearing all browser-stored files and try connecting again.
Just don’t forget to back up your passwords, as this procedure will delete those, too.
Follow these steps to clear the browsing data in Mozilla Firefox:
- Press Ctrl + Shift + Delete to open the Clear browsing data dialog box.
- Check all boxes and select Everything under the Time range.
- Click Clear now.
3: Disable Add-ons
Even though this is a long shot, disabling Add-ons might help. This especially applies to proxy/VPN extensions which hide your IP address and replace it with the public one.
They are only browser-based, and, in my own experience, free options never worked for me. They either have a low data limit or slow down the bandwidth substantially.
Paid solutions are much better but they still fall short in comparison to VPNs.
Here’s how to disable Add-ons in Mozilla Firefox temporarily:
- Open Firefox.
- Click on the hamburger menu and expand Help.
- Choose Restart with Add-ons disabled.
- Click Restart.
- Try accessing any sites and look for improvements.
And this is how to disable them for good:
- Press Ctrl + Shift + A to open the Add-ons menu.
- Disable every add-on individually and restart Firefox.
- Look for changes.
4: Disable IPv6, Proxy, and DNS Prefetching
Mozilla Firefox works with the IPv6 rather than with the IPv4. If you’re for some reason sticking with the IPv4 protocol solely, we recommend disabling the IPv6 in Mozilla Firefox.
This should avoid further issues and the aforementioned error should be dealt with. In addition, if you don’t use the general Proxy server settings, we suggest disabling this option, too.
And, finally, disable the DNS Prefetching. This feature allows Firefox to load uncached sites faster.
Here’s how to disable IPv6 in Mozilla Firefox:
- Open Firefox.
- Type about:config in the address bar and press Enter. Accept the risk.
- Search for IPv6 in the search bar.
- Right-click on network.dns.disableIPv6;false and click Toggle.
And these steps should show you how to disable Proxy:
- Click on the hamburger menu and open Options.
- Scroll to the bottom and open Settings under the Network Proxy.
- Select No proxy and click OK to confirm changes.
Finally, here’s how to disable the DNS Prefetching option:
- Repeat the first 2 steps from the IPv6 instructions.
- Right-click on the list and select New > Boolean from the contextual menu.
- In the preference dialog box, type network.dns.disablePrefetch and press Enter.
- Set the preference as True and restart Firefox.
5: Reinstall Mozilla
In the end, the only thing we can think of concerns the clean reinstallation of Mozilla Firefox. This might be the long shot, but there’s always the danger of some hidden error.
Things sometimes tend to go awry after an update, so there’s also that. When we say ‘reinstallation’, we refer to cleaning everything and starting from a scratch.
In order to clean reinstall Mozilla Firefox, follow the steps we provided below:
- In the Windows Search bar, type Control and open Control Panel from the list of results.
- From the Category view, click Uninstall a program under Programs.
- Right-click on Mozilla Firefox and Uninstall it.
- Use IObit Uninstaller (suggested) or any other third-party uninstaller to clean all remaining files and registry entries related to Firefox.
- Restart your PC.
- Download Mozilla Firefox, here. Install it and try connecting again.
That should do it. In case you’re still unable to address this, we recommend sending a ticket to Mozilla support. On that note, don’t forget to share your questions or alternative solutions with us and our readers in the comments section below.
FAQ: Learn more about browsers
- Why some websites are not opening in Firefox?
Firefox may fail to find and load particular websites due to incorrect proxy and DNS settings, malware, Internet connection issues or corrupted or missing browser files.
- How do I stop Firefox from blocking websites?
Follow these steps to stop Firefox from blocking websites:
- Navigate to Settings > click on Options
- Select Privacy & Security > go to Content Blocking
- Click on the Manage Exceptions button and select the websites you want to disable blocking for.
- How do I check if Firefox is permitted to access the Web?
Here’s how to check if your computer settings allow Firefox to access the web:
- Go to Settings > Update & Security
- In the left-hand pane, click on Windows security
- Under Protection areas, click on Firewall & network protection
- In the Security Center, click Windows Firewall
- Click on Allow an app through firewall
- Make sure Firefox is in the list of the allowed apps.
Editor’s Note: This post was originally published in May 2018 and has since been updated for freshness and accuracy.