Is It Down or Just Me? The Ultimate Step-by-Step Diagnostic Guide
When a critical website refuses to load, follow this definitive 6-step checklist to isolate local DNS issues, ISP route failures, browser cache glitches, and genuine server outages.
- Learn how to distinguish local browser or router issues from global cloud outages.
- How to test whether your cellular network can load what your home Wi-Fi cannot.
- Commands to flush your OS-level DNS cache on Windows, macOS, and Linux.
- How anycast CDNs (Cloudflare, AWS CloudFront) can be partially down in one region while healthy elsewhere.
1. The Four Layers of Website Accessibility
When you enter a URL like "github.com" or "bank.com" into your browser, your connection passes through four distinct layers: your local device environment, your local Wi-Fi router, your Internet Service Provider (ISP), and finally the target website's hosting network.
A breakdown at any one of these four boundaries produces almost identical browser errors—most commonly ERR_CONNECTION_TIMED_OUT, ERR_NAME_NOT_RESOLVED, or a generic blank screen.
This is why an independent probe like ItsUporDown is essential: by probing the target domain directly from independent cloud edge servers across global datacenters, you immediately isolate whether the server is physically answering requests to the world.
2. Step 1: The Cellular Data Bypass Test
The fastest physical diagnostic test takes less than ten seconds: turn off Wi-Fi on your smartphone and attempt to open the website using pure 4G/5G mobile cellular data.
If the website loads immediately on cellular data but fails on your laptop or home computer, the issue is 100% confirmed to be local to your home network, local DNS resolver, or broadband ISP.
- If cellular also fails and ItsUporDown reports the server is DOWN, the website is experiencing a widespread hosting outage.
- If cellular loads but home Wi-Fi fails, proceed to flush your computer DNS cache.
3. Step 2: Flush Your Operating System DNS Resolver
Operating systems cache domain-to-IP resolutions aggressively. If a website recently migrated servers or updated its DNS records, your computer may be querying an old, decommissioned IP address while the rest of the world has already transitioned to the new servers.
Flushing your operating system DNS cache clears stale records and forces your computer to request fresh authoritative nameserver records.
# Windows (Command Prompt or PowerShell) ipconfig /flushdns # macOS (Terminal) sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder # Linux (systemd-resolved) sudo resolvectl flush-caches
4. Step 3: Test Alternative Public DNS Resolvers
Many home broadband providers operate proprietary DNS servers that suffer regional routing failures, content filtering bugs, or slow TTL refreshes.
Switching your network adapter or router configuration to trusted public recursive resolvers often immediately restores access to websites that your ISP resolver fails to resolve.
Recommended global anycast resolvers include Cloudflare DNS (1.1.1.1 and 1.0.0.1) and Google Public DNS (8.8.8.8 and 8.8.4.4).
5. Step 4: Rule Out Browser Extensions & VPN Routing
Aggressive ad blockers, privacy extensions, or stale proxy configurations frequently intercept and block HTTPS requests silently.
Always test the website in an incognito or private browsing window with all extensions disabled. Furthermore, if you are connected to a corporate VPN or residential proxy, disconnect and test again, as many hosting providers employ Web Application Firewalls (WAF) that automatically block VPN IP subnets.
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