1. Mismanaged Domain Name/SSL

Domain Name Expired

A website will not load when the domain name is expired and even worse, the email associated with that domain will stop working too.

Domain Name Improperly Setup

When the domain is not setup properly the website and/or email will stop working. In order for the domain name to work the DNS needs to be configured properly.

SSL Misconfigured

If the SSL is not setup properly on your website, or it’s expired, the site users will see a security warning or other message related to SSL. This will make users distrust the website security.

Solution: Ensure that someone is actively managing the domain name(s) and SSL certificates. Don’t let your domain name or SSL expire. It may take up to 48 hours to get everything working again!

2. Site Blocked by a Filter

If your website doesn’t open for you, but does open for others, it could be one of the following situations:

• Webhost server is blocking the IP address of your ISP

• Your ISP is blocking the webhost server IP address

• Your LAN/Firewall is blocking the webhost server IP address

• 3rd party filter is blocking the webhost server IP address

Solution: Try opening the website on a different computer connected to a different ISP on a different network. If it works for others but not for you, then it is very possible it is being blocked.

3. Coding Malfunction

Malfunction of Local Code

Coding malfunction can be caused for many reasons including updates or upgrades to the following:

• Hosting server operating system (OS)

• Computer browser (e.g. Chrome, Safari, Firefox, IE, etc.)

• CMS or web framework

Malfunction of 3rd Party Code

Websites and web applications use a variety of 3rd party codes. This code is used because it saves the developer a tremendous amount of time not having to reinvent the wheel, but rather borrowing or using code developed and maintained by others. The challenge, however, is that a 3rd party code may or may not be kept up-to-date with current web environments. Outdated scripts create security vulnerabilities and malfunction of a website/application. The following are examples of common types of 3rd party codes:

• Scripts

• Code in iFrames

• Plug-ins

• Addons

• Extensions

• Widgets

Solution: 3rd party codes needs to be identified and managed to ensure it is updated and compatible with the latest standards. Ultimately, you should encourage the owner of the site to review his or her website regularly to make sure everything works as expected. The owner of the site should pay special attention to areas that use 3rd party integrations or complex functionality.

4. Server Failure

Server Hardware Failure

The server’s physical hardware (like the hard drive or processor) is defective or unresponsive, which means the website stops working, is sluggish, or works intermittently.

Server Software Failure

The server’s operating system (e.g. Linux or Windows) is outdated, incompatible or corrupted.

Solution: Save yourself much trouble and time by hosting your code in a reputable data center managed by competent staff. Here at IT Hands we partner with Rackspace for our hosting.

5. Malware/Hacked Site

Sometimes it is very obvious to the visitor that your site has been hacked. (Example: the hacker may change text on your site or upload photos to it). Other times a visitor to the site may not notice the issue. (Example: some code may be installed on the site to collect certain info and then send it to an unauthorized 3rd party). In any case, having malware on your site is a serious issue.

Solution:

• Use strong passwords and change your admin password regularly

• Ensure your password is not stolen

• Only install reputable third party add-on/plugins

• Use an online tools (like http://sitecheck.sucuri.net) to check the health of your website

• Encourage your clients to proactively review their websites regularly and make sure everything works for them as expected

6. Browser Incompatibility

When the website loads but does not display properly, it may be that you have a browser issue. Before making a site live, your IT partner should check your website for compatibility with the current and most popular versions of the Browsers (Chrome, Safari, Internet Explorer, FireFox, etc.). However, just because it works today does not mean it will render or function properly on future browser versions (or old versions).

Solution: There are some browser testing tools available but they are not 100% effective. The only proven way to ensure browser compatibility is to visit the website using different browsers.

Source : https://www.ithands.com/blog/6-reasons-why-a-website-stops-working