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HTTP404

Description

The 404 error occurs when employees visit a website, but the page they are trying to access does not exist. Although the server is reachable, the specific page employees are looking for is not because it either doesn’t exist or is broken.

The 404 error

Possible causes

  1. The page is missing from the website or is unavailable.

  2. The website address was typed incorrectly.

  3. There is an issue with the browser cache.

  4. The website is blocked by ISP or company, although this may not be directly reported as a 404 error.

  5. Invalid connection configuration, e.g., when connecting to the company’s intranet, a VPN connection may need to be established first.

What could be causing this type of Problem?

The most common cause of the error is an incorrectly typed URL. Sometimes the problem occurs on the server-side and requires examination. The 404 error code can appear in any browser: Edge, Chrome, or Firefox.

In most cases, this is an isolated incident concerning an individual device that happens to be accessing Internet (or intranet) locations that have, for some reason, changed since the last visit. In this case, individual fixes can be applied as outlined below.

If this is a widespread incident, consider the following questions:

  • Has your browser been recently updated?

  • Has there been a change to the network resulting in a different route or path needed to be taken to the website’s destination?

  • Are the devices using a predefined proxy server to get to their destination?

  • Has the destination, usually a website, been altered or changed?

Read the suggestions below to find out how Nexthink can help solve these problems.

How to Scope this issue

The first step is to scope the issue to understand how serious or widespread the problem is.

Scoping with Applications

Using Applications Reliability dashboards, look at the various breakdowns and filter them to find correlations. For instance, specific errors could be present on:

Specific applications only

In this instance, try to understand what has changed concerning a particular web application.

Specific OS, browser version

Has the OS or browser version changed? Has the browser been updated recently? Using Nexthink, investigate the performance of various browser versions to understand if a specific version is experiencing the problem.

Specific hierarchy nodes

If an infrastructure component such as a network change, a proxy server, or something similar is causing the problem, then it is likely to be shown by a specific area in the hierarchy containing a high quantity of errors.

Specific key pages or URLs

Most likely, a change was made at the web app level. Contact the appropriate application support team and inform them of the problem.

Specific time frames only

Examine if it is a one-time event that must be investigated, or whether this is a recurring event where something on the network, e.g., corporate backup, may be altering the availability of the network.

Scoping with Nexthink Finder (classic)

In this case, you can search for failed connections with the Applications console and start an investigation in Finder. By entering the web address as a criterion in Finder and checking all connections to that domain or website, Finder returns valuable insights into the scope of the issue.

If a proxy server is in question, then Nexthink Finder can help better understand if this is the root cause. Create an investigation targeted at the domain name of the application in question and note whether most of the device traffic is going through a particular proxy. It is also possible to make the proxy server the actual target of the investigation itself and then use it to show various analytics such as the number of failed requests or response times from the proxy. This approach will reveal any unexpected behaviors.

If available, reconfigure the device to an alternative proxy server. If the requested web page loads correctly, it is a good indication that the company’s proxy server may be the cause of the problem. Inform the teams responsible for the networking and proxy infrastructures within the organization of the issue and the scope of affected devices.

If a website is returning a 404 error on multiple URLs but is accessible on other networks, e.g., a mobile network, then the ISP or company might have blocked access to the website, or an ACL or firewall on the router is blocking access. Known sites that promote software or video piracy are routinely blocked by ISPs, while the company may block other sites such as social media (Facebook, Twitter).

This may affect one or all applications depending on where the issue resides.  If it affects all web requests, then access to several websites from various devices in various regions will be affected. 

Contact the IT infrastructure team, inform them of the scope of the issue, and request their assistance.

Possible Solutions

Fixing Employee Devices  

NOTICE: Consider the scoping procedures first, see the steps above.

Be aware of the scope of impact when running corrective actions using Nexthink. If you are dealing with a single device or just a few devices, the Remote Actions can be run in the background while providing help to the affected employees or they can even be performed silently.

Should the scoping reveal that the incident is widespread, the issue will require more attention. We recommend employing Engage Campaigns to ensure that affected employees will get a visual notification of any changes being performed through remote actions at scale because employees may not be aware of the Remote Action taking place.

Refresh the page

Refreshing the page can be a quick way to fix the problem because usually, the error is a temporary one. Press CTRL+F5, which works on most browsers, or refer to your documentation if needed.

Try another website

Try to access the same website on another device within the same network. If the access fails, it is a strong indication that there may be more serious network issues. If the access works, then it is a local device issue.

Double Check the Address

If you typed the URL into the address box yourself, you might have mistyped it. If you clicked a link on another webpage and were shown a 404 error, it is possible that the link was defined incorrectly. Check the address and see if you can spot any obvious errors.

Mistyped URL is a common mistake that generates the 404 error

Check if other users have the same error on the same URL with the Applications reliability dashboard. There could be a link in a business application pointing to this address that should be updated.

Clear cache

If the cache hasn’t been cleared for a while, some of the files within it may be corrupt. Clearing the cache can help. Select the Basic data clearing option if the user does not want to lose saved passwords and other personalized data.

Use the remote actions to clear the browser cache on Edge or Chrome (‘Clear Edge / Chrome Settings’). Clearing of the cache can be carried out remotely to assist the user.

Check if the Website Has Temporary Issues

Sometimes a website may be experiencing temporary issues which may cause 404 errors. Although this is not a technical fix, explore the Applications console to check how and when the 404 errors started.  You may notice that they are occurring in a particular time frame or regularly during a specific part of the day. The information provided in Applications brings valuable insights to the server team so they can understand and examine why the website is down.

Confirm correct connection configuration

It may be necessary at times to activate a VPN to reach the DNS Servers required for name resolution. This is especially true for remote employees wanting to connect to the company’s resources, such as the intranet. In this case, confirm with the employee that their VPN is connected, and if not, establish a connection and then check the access. If the problem has been solved, it should provide an insight into the same connection issue on other remote devices. Employees can be reached using an Engage Campaign to be reminded of this requirement.

Infrastructure fixes

Site blocked by ISP or company firewall

If a website is returning a 404 error on multiple URLs but is accessible on other networks, e.g., a mobile network, then the ISP or company might have blocked access to the website, or an ACL or firewall on the router is blocking access. Known sites that promote software or video piracy are routinely blocked by ISPs, while the company may block other sites such as social media (Facebook, Twitter).

In this case, you can search for failed connections with the Applications console and start an investigation in Finder. By entering the web address as a criterion in Finder and checking all connections to that domain or website, Finder returns valuable insights into the scope of the issue.

This may affect one or all applications depending on where the issue resides.  If it affects all web requests, then access to several websites from various devices, in various regions will be affected. If it is just one update to a router or firewall that has blocked a particular website, then the issue is more specific. Contact the IT infrastructure team, inform them of the scope of the issue, and request their assistance.

Confirm Name Resolution

There may be an incorrect name resolution either on the client or server-side. It does not mean that the name does not resolve, which would normally generate an ERR_NAME_NOT_RESOLVED error, but rather that it is resolving to the wrong address and pointing the URL to a different site.

In this instance, the DNS Server team should be contacted and informed that the name of the IP resolution for the website appears to be incorrect. They can resolve the issue on the server-side by checking the records in the Zone database and flushing the server-side cache.

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