Fix Http/1.1 Service Unavailable error in Firefox

Here is a full guide on how you can fix the “Http/1.1 Service Unavailable” error in Firefox browser. A lot of users have faced this error message when trying to open specific websites or visiting the Unified Gateway logon page or using services from Citrix, Netscaler, Apache, etc.\. Now, there can be different reasons as to why this error is triggered. Let us try and understand the reasons that cause this error.

What does Server Unavailable mean?

Server unavailable basically means that the website’s server is unavailable right now and the server can’t take the request by a user. It can occur if the server is too busy or it is down for maintenance – but there can be other reasons too.

Why is Http/1.1 Service Unavailable triggered?

Here are some of the possible causes that might trigger the “Http/1.1 Service Unavailable” error:

• This error can be a result of some temporary and minor bugs or glitches. In that case, you can try performing a power cycle or refreshing your browser to fix the error.
• The problem might lie within your browser like outdated browser version, corrupted browser cache, etc. You update your browser and clear the browser cache to get rid of the issue.
• In some instances, the error can be caused if an incorrect date & time is set on your system. If the scenario applies, you can adjust the date & time accordingly.
• It can also be caused due to malware or virus that is infecting your PC. You can run a malware scan to check for viruses and remove them from your system.
• A poor internet connection can be another reason for the same error.
• Other reasons for this error can be DNS issues, Windows add-ons, etc.

In any scenario, we have got various working solutions that will help you fix the error. Let us check out.

Fix Http/1.1 Service Unavailable error in Firefox

Here are the methods to resolve the “Http/1.1 Service Unavailable” error on Windows PC:

1. Try some general suggestions.
2. Access the Unified Gateway page.
3. Make sure the correct Date & Time is set on your device.
4. Clear the SSL state.
5. Delete Cache and Temporary Files.
6. Disable Windows Add-Ons.
7. Run Malware Scan.
8. Clear DNS Cache.
9. Change the DNS Server.
10. Allow Exception to the Windows Firewall.

1] Try some general suggestions

At first, you can try some preliminary basic fixes to get rid of the error. These fixes should be able to counter the error in case some minor bugs or glitches are causing the error. Here are the fixes:

You can try rebooting your PC and see if it fixes the error. A simple restart might not fix the error. So, in that case, you can perform a power cycle. So, disconnect your device from the internet, switch off the router, and then shut down your PC completely. Now, wait for a few minutes and then switch on your PC and router. Try visiting the problematic website and see if the error is now fixed.

Try refreshing your web browser using Ctrl + R hotkey and see if the error is fixed. You can also close the web browser, wait for 2-3 minutes, and then restart the browser to check whether the problem is fixed.

Another thing you can do is make sure you have an up-to-date web browser. If not, update your web browser and see if the error is fixed.

The “HTTP/1.1 Service Unavailable” error can be a result of a poor internet connection. So, make sure you are connected to a stable internet connection. You can try troubleshooting your network and internet issues if there are any.

If these tricks don’t fix the error, go ahead with the next potential fix.

2] Access the Unified Gateway page

This error can be triggered because of the reachability issue to the Storefront server from the Netscaler. If the scenario is applicable, you can try adding the storefront server as a service and then access the unified gateway page to fix the error. Here is how you can do that:

1. First, add a storefront server as a service and then try connecting the monitors such as ICMP or TCP defaults in order to check for the connectivity or some port issue.
2. Next, for storefront IP, allow the 443 ports through the firewall.
3. Now, open the storefront settings, and in the Unified Gateway configuration, make sure you are not dealing with any 443 port mismatched issues.
4. After that, see if the following expression is missing from the storefront store name:

   REQ.URL.PATH.SET_TEXT_MODE(IGNORECASE).STARTSWITH(“/Citrix/STORE_NAME

   You can then add the above line into the content switch policy.

5. You can try accessing the unified gateway page.

See if the error is fixed now. if not, try the next fix.

3] Make sure the correct Date & Time is set on your device

The error can also be caused in case you have set an incorrect date & time on your system. In that case, simply adjusting the date & time should help you fix the issue. Just right-click on the time on your taskbar and then click on the Adjust date and time option. Then, enable the toggle associated with the Set time automatically and Set time zone automatically options. After doing so, check whether or not the error is resolved.

4] Clear the SSL state

Some users have reportedly fixed the error by clearing the SSL state in Internet Properties. The error can be caused if the SSL state is corrupted and led to an SSL connection error. In that case, you can try clearing the SSL state using the below steps:

1. Press Win+R to open the Run dialog and enter “inetcpl.cpl” in it to open up the Internet properties window.
2. Navigate to the Content tab and tap on the “Clear SSL State” option.

When the SSL state is cleared, see if the error is resolved.

See: HTTPS sites not opening in any browser on Windows computer.

5] Delete Cache and Temporary Files

This error can be caused due to the bad or corrupted cache and temporary files stored in your web browser. So, you can try clearing your cache from your browser and then see if the error is fixed.

6] Disable Windows Add-Ons

Some add-ons enabled on the internet connection by Windows can also trigger the error. In that case, you can resolve the error by disabling Windows add-ons using the below steps:

1. Firstly, press the Run dialog box and enter inetcpl.cpl in to launch the Internet Properties window.
2. Now, go to the Programs tab and click on the option called Manage Add-Ons.
3. Next, click on the drop-down option present under the Show title and choose the “Add-ons that have been used by browser” option.
4. After that, right-click on add-ons present there and then select the Disable option. Repeat it for all the add-ons.
5. When done, close the Manage Add-ons window.
6. Finally, click on the Apply > OK option to save changes.

You can now try visiting the same website throwing the error and see if it is now fixed.

7] Run Malware Scan

In case this error is triggered by a virus or malware infection on your system, you should try scanning your system for malware using Windows Defender. If you use a free third-party antivirus, you can use it to scan and fix malware on your PC.

See: How to fix HTTP Error 304 Not modified error?

8] Clear DNS Cache

Another thing you can try to fix the issue is clearing the DNS cache. The issue might be in the DNS of the client-side that is triggering the error at hand. So, flushing the DNS cache should help if and only the scenario is applicable. You can follow the below steps to do that:

1. Firstly, open an elevated Command Prompt window.
2. Now, enter the below command in CMD:

   ipconfig /flushdns

3. After that the command is fully executed, try visiting the website that was giving you the “Http/1.1 Service Unavailable” error. Hopefully, the error is fixed now.

9] Change the DNS Server

Inconsistency with your DNS server can also cause this error. Hence, try switching your DNS server to Google DNS and see if it fixes the error for you. Some affected users have fixed the error using this method and it might work for you as well. You can change to Google DNS by using the below steps:

1. Open Run using Win+R and enter “ncpa.cpl” in it to bring up the Network Connections window.
2. Right-click on your internet connection and then select the Properties option.
3. Select the Internet Protocol Version 4 (IPV4) option and click the Properties button.
4. Choose the Use the following DNS server addresses option and then fill the following values in respective fields:
   -Preferred DNS server: 8.8.8.8
   -Alternate DNS server: 8.8.4.4
5. Press the OK button and close the window.

Check whether the error is resolved now.

How do I fix HTTP 1.1 Service Unavailable?

There are several things you could do to fix this error in the Firefox browser. For example, you can disable Windows add-ons, clear the SSL state, delete cache and temporary files, clear the DNS cache, change the DNS server, etc. However, as it is most likely a server-side problem, you may not find the exact solution as a user.

How do I open a Service Unavailable website?

As a user, you can try deleting your cache and cookies of the website. Since it is a server-related problem, the administrator of the website needs to check various things to make the website online. On the other hand, you could clear the SSL state, rectify your date and time settings, etc.

That’s it!

Now read:

• Web apps HTTP Error 503 and WAS event 5189 on Windows.
• Fix ERR HTTP2 Inadequate Transport Security error in Google Chrome.