Why Websites Go Down: Common Causes, Warning Signs and How to Detect Downtime

Common causes of website downtime

Outages feel mysterious, but most trace back to a handful of places. Knowing them helps you ask the right question of your developer or hosting provider.

DNS errors

DNS translates your domain name into the server address. If records are wrong, missing or the domain's nameservers fail, visitors cannot find you even though the server is healthy. Common triggers are an expired domain, a mistaken record edit and a migration where records were not updated. A DNS checker shows what the world currently sees for your domain.

Hosting and server resource problems

Servers run out of memory, CPU, disk space or database connections. A traffic spike, a runaway process, a full disk from logs or backups, or a plan that is simply too small can each take a site offline or make it painfully slow. Shared hosting can also suffer from a noisy neighbour. If this keeps happening, the answer is usually better-sized hosting rather than more patching.

Failed deployments and updates

Code releases, plugin or theme updates and database changes are a leading cause of self-inflicted outages. A missing file, an incompatible plugin or a migration that fails halfway can produce a blank page or a server error. Staging environments, backups and a rollback plan reduce the risk.

Expired certificates and configuration problems

An expired SSL/TLS certificate makes browsers show a full-page security warning, which is effectively downtime for most visitors. Other configuration slips — a wrong redirect rule, a firewall blocking real traffic, a misconfigured web server — have a similar effect. You can verify a certificate with our SSL checker.

Third-party dependencies and attacks

Sites often rely on external services such as a CDN, payment provider or login service. When one fails, parts of your site can break while the homepage still loads. Malicious traffic or a compromised server can also cause outages; if you suspect compromise, treat it as a security incident rather than a routine fix.

Warning signs that often come before an outage

• Pages getting slower over days or weeks.
• Intermittent errors that vanish when you refresh.
• Hosting alerts about disk, memory or bandwidth limits.
• A certificate or domain renewal date approaching with no one assigned to it.
• Updates waiting for months, or a recent change nobody tested properly.
• Customers reporting that the site “sometimes doesn't load.”

None of these guarantees an outage, but each is a reason to look sooner rather than later.

What the HTTP status codes tell you

When a monitor requests your page, the server's response code gives a first clue.

How uptime monitoring works

An uptime monitor is a service that requests your web address on a schedule — often every few minutes — from its own servers. For each check it records whether a response arrived, the HTTP status code and how long it took. If checks start failing, it raises an alert.

Two details matter. First, the check frequency sets how quickly you find out: with five-minute checks you will learn of an outage within about that window, and an outage shorter than the gap can slip between checks. Second, a basic monitor tests that your address answers; it does not confirm the page content is right or that a login, search or checkout works. Where a tool supports it, checking a dedicated health page or a specific expected piece of content gives a stronger signal.

Failure confirmation and avoiding false alarms

The internet is not perfectly reliable. A single dropped request, a brief network hiccup between the monitor and your host, or a moment of heavy load can cause one failed check on a perfectly healthy site. If every failure triggers an email, people soon learn to ignore the alerts.

Well-designed monitoring handles this with confirmation: after a failed check it retries a few times in quick succession, and only treats the site as down if the failures persist. It then opens one incident and sends one alert — not a new email on every failed check — and records when the incident started so you can see the length of the outage later.

Recovery notifications and incident history

Knowing a site is back matters almost as much as knowing it went down. A recovery notification lets you stop investigating, tell customers it is resolved and spot sites that flap between up and down. Incident history — start time, recovery time, duration and reason — helps you see patterns, such as outages that always happen after Friday deployments or at peak traffic.

SiteBuddy is Xigmapro's uptime monitor built around these ideas: scheduled checks, retry-based confirmation, one email when a confirmed outage starts and one when it recovers, plus incident history. It tests that your address responds; it does not test application logic.

When to contact a developer or your hosting provider

• Call your hosting provider when the server is unreachable, resources are exhausted, or the provider's status page reports an incident.
• Call your developer when errors started after a change, when you see 500-series errors, or when only part of the site is broken.
• Call your domain registrar or DNS provider when the domain does not resolve or a renewal has lapsed.
• Treat it as a security issue if you notice unexpected content, redirects or files you did not add — see our guide to what a website malware scanner can and cannot detect.

If outages keep recurring, an ongoing website maintenance plan puts someone in charge of updates, backups and monitoring before problems become incidents.