Why Is a Website Down? 8 Common Causes

Websites go down for surprisingly ordinary reasons. Here are the eight most common ones, what they look like from the outside, and what can be done about each.

A website is really just software running on a computer somewhere, connected to the internet through several layers of infrastructure. A failure in any of those layers can take the whole site offline. Sometimes the cause is dramatic, like a cyberattack; far more often it's something mundane, like a forgotten renewal or a deploy gone wrong. Understanding the usual suspects helps you tell a quick blip from a serious outage — and, if it's your own site, where to start looking.

1. The web server crashed or ran out of resources

The most direct cause: the server process that answers requests has stopped, frozen, or exhausted its memory or CPU. When this happens, visitors typically see a connection error, a blank page, or a 500 Internal Server Error. Shared hosting plans are especially prone to this, because a spike from one site on the server can starve the others.

What helps: for site owners, restarting the service usually restores things immediately, but the real fix is finding what exhausted the resources — a memory leak, an inefficient query, or simply too little capacity. For visitors, there's nothing to do but wait and re-check.

2. The domain name expired

Domains are rented, not owned, and they have to be renewed (usually yearly). If the owner misses the renewal, the domain stops resolving and the site vanishes — often replaced by a parking page full of ads. This is one of the most avoidable outages, and also one of the most embarrassing, because even huge companies have done it.

What helps: owners should enable auto-renew and keep billing contacts current. Visitors can sometimes confirm the cause with a quick WHOIS lookup, which shows a domain's expiry date.

3. DNS problems

DNS is the internet's address book: it translates a human-friendly name like example.com into the numeric IP address of the server. If DNS records are misconfigured, deleted, or a DNS provider has an outage, browsers can't find the server even though the server itself is perfectly healthy. DNS changes also take time to propagate, so a recent edit can cause intermittent failures for hours.

What helps: owners should double-check records after any change and use a reliable DNS provider. Visitors can try flushing their local DNS cache or switching to a public resolver like 1.1.1.1 or 8.8.8.8.

4. A traffic spike overwhelmed the site

Getting featured on the news, going viral, or landing on the front page of a big site can send more visitors than the server can handle. The result is the same as a crash: slow responses, timeouts, or errors. Ironically, success causes the outage.

What helps: caching, a content delivery network (CDN), and auto-scaling let a site absorb surges. For visitors, these outages usually pass once the rush dies down.

5. A DDoS attack

In a distributed denial-of-service (DDoS) attack, an attacker floods a site with bogus traffic from many machines at once, deliberately exhausting its capacity so real visitors can't get through. From the outside it looks like a severe slowdown or total outage.

What helps: dedicated DDoS-protection and CDN services (such as those that filter traffic before it reaches the origin) are the standard defense. There's nothing a visitor can do except wait it out.

6. A bad deployment or code change

Many outages are self-inflicted: a developer pushes an update with a bug, a broken configuration, or a missing file, and the site breaks the moment it goes live. These outages tend to start abruptly right after a release and often produce 500-class errors or a partially broken page.

What helps: staging environments, automated tests, and the ability to roll back quickly. This is one reason outages sometimes resolve within minutes — someone reverted the change.

7. An expired or misconfigured SSL certificate

The padlock in your browser depends on a valid SSL/TLS certificate. Certificates expire, and if one isn't renewed, browsers show a full-page security warning that scares visitors away — effectively an outage even though the server is running. Misconfigured certificates (wrong domain, incomplete chain) cause similar warnings.

What helps: automated certificate renewal (now common and often free) prevents this. Visitors who trust the site can sometimes proceed past the warning, but it's wise to be cautious.

8. The hosting provider or data center had an outage

Sometimes the site and its owner did everything right, but the company hosting it suffered an outage — a power failure, network problem, or large-scale cloud incident. When a major cloud region goes down, thousands of unrelated websites can drop at once.

What helps: for owners, redundancy across regions or providers reduces the risk, though at a cost. For everyone else, these are wait-and-see situations; the host's own status page is the place to watch.

So is the site really down?

Whatever the cause, the first practical step is confirming the outage is real and not something on your end. Our free checker connects to the site from our server and tells you whether it responds, and our guide on whether a site is down for everyone or just you walks through how to narrow it down. If you're seeing a specific error code, the HTTP status codes guide explains what it means.