Encountering website errors can be frustrating, whether you’re a visitor, developer, or site owner. From 404 pages to server crashes, these issues disrupt user experience and hurt SEO.
This comprehensive guide covers:
✅ The most common types of website errors
✅ What causes them (and who’s responsible)
✅ Step-by-step fixes for each error
✅ Pro tips to prevent future issues
Let’s dive in and get your site running smoothly again!
Types of Website Errors (And What They Mean)
Website errors fall into four main categories:
1. Client-Side Errors (4XX)
These occur due to user or browser issues.
| Error Code | Meaning | Common Causes |
|---|---|---|
| 400 Bad Request | Server can’t process the request | Malformed URL, corrupt cookies |
| 401 Unauthorized | Login required | Incorrect credentials, expired session |
| 403 Forbidden | Access denied | File permissions, IP blocking |
| 404 Not Found | Page doesn’t exist | Broken link, deleted page |
| 429 Too Many Requests | Rate limit exceeded | Too many login attempts, API abuse |
2. Server-Side Errors (5XX)
These mean the website’s server failed.
| Error Code | Meaning | Common Causes |
|---|---|---|
| 500 Internal Server Error | Generic server failure | Coding bugs, misconfigurations |
| 502 Bad Gateway | Proxy/server communication issue | Overloaded server, faulty firewall |
| 503 Service Unavailable | Server down for maintenance | High traffic, server updates |
| 504 Gateway Timeout | Server response too slow | Network lag, backend failure |
3. DNS & Connectivity Errors
These prevent accessing the site entirely.
| Error | Meaning | Common Causes |
|---|---|---|
| DNS_PROBE_FINISHED_NXDOMAIN | Domain doesn’t exist | Wrong URL, DNS misconfiguration |
| ERR_CONNECTION_TIMED_OUT | Can’t reach the server | Internet issues, firewall blocking |
| ERR_NAME_NOT_RESOLVED | DNS lookup failed | Incorrect DNS settings |
4. SSL/TLS Certificate Errors
These indicate security issues.
| Error | Meaning | Common Causes |
|---|---|---|
| NET::ERR_CERT_AUTHORITY_INVALID | Untrusted certificate | Expired SSL, self-signed cert |
| SSL_ERROR_BAD_CERT_DOMAIN | Wrong domain for certificate | Misconfigured HTTPS |
How to Fix Common Website Errors (Step-by-Step)
Fixing 4XX Errors (Client-Side Issues)
404 Not Found
✅ For Users:
- Check the URL for typos.
- Use the site’s search bar.
- Contact the website owner.
✅ For Site Owners:
- Set up 301 redirects for deleted pages.
- Create a custom 404 page to guide users.
403 Forbidden
✅ For Users:
- Clear browser cache/cookies.
- Try accessing from another device.
✅ For Site Owners:
- Check file permissions (CHMOD 755 for folders, 644 for files).
- Disable hotlink protection if blocking legit traffic.
Fixing 5XX Errors (Server-Side Issues)
500 Internal Server Error
✅ For Users:
- Refresh the page (
Ctrl + F5). - Try later—could be temporary.
✅ For Site Owners:
- Check server error logs (
/var/log/nginx/error.logor similar). - Disable faulty plugins (WordPress) or recent code changes.
502 Bad Gateway
✅ For Users:
- Switch browsers (Chrome → Firefox).
- Restart router/modem.
✅ For Site Owners:
- Restart NGINX/Apache (
sudo systemctl restart nginx). - Increase PHP memory limit if running WordPress.
Fixing DNS & Connectivity Errors
DNS_PROBE_FINISHED_NXDOMAIN
✅ For Users:
- Use Google DNS (8.8.8.8 / 8.8.4.4).
- Flush DNS cache (
ipconfig /flushdns).
✅ For Site Owners:
- Verify DNS records in cPanel/Cloudflare.
- Ensure domain isn’t expired.
Fixing SSL Errors
NET::ERR_CERT_AUTHORITY_INVALID
✅ For Users:
- Click “Advanced” → “Proceed to site” (if safe).
- Check system date/time.
✅ For Site Owners:
- Renew SSL certificate (Let’s Encrypt, Cloudflare).
- Ensure HTTPS redirects are properly configured.
How to Prevent Website Errors
✔ Monitor uptime (UptimeRobot, Pingdom).
✔ Update CMS/plugins (WordPress, Joomla).
✔ Use a CDN (Cloudflare, Akamai) to reduce server load.
✔ Test backups regularly.
✔ Check Google Search Console for crawl errors.
FAQs: Website Errors Explained
Q1: What’s the most common website error?
A: 404 Not Found, usually due to broken links.
Q2: How do I check if a website error is my fault?
A: Test on multiple devices/networks. If it works elsewhere, the issue is on your side.
Q3: Can website errors hurt SEO?
A: Yes! 5XX errors reduce crawlability; 4XX errors waste backlinks.
Q4: How do I find hidden server errors?
A: Use Google Search Console > Crawl Errors or server logs.
Q5: Should I contact my host for 5XX errors?
A: Yes, if you can’t resolve them via logs or caching.
Final Thoughts
Website errors are inevitable—but fixable. Most 4XX errors are user-side, while 5XX errors need developer attention. Regular maintenance prevents most issues.