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Website Blocked or Access Denied

A site you need for work returns "Access Denied," ERR_BLOCKED_BY_ADMINISTRATOR, or just won't load? Work through these steps in order — step 1 tells you who's actually responsible.

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Website Blocked or Access Denied

A site you need for work is blocked, returns an error, or just won't load

⚠ Common symptoms

  • "ERR_BLOCKED_BY_ADMINISTRATOR" or "Access Denied" in the browser
  • Site loads fine on mobile data or at home, but not on work Wi-Fi
  • A specific tool or platform loads its homepage but blocks login
  • Your browser shows a certificate warning before the block page
  • 1

    Identify who is blocking the site

    The block message usually tells you: browser-level block says "Your administrator has blocked this site." Network-level block (firewall/DNS filter) shows a branded page from Cisco Umbrella, Forcepoint, or Zscaler. Knowing the source tells you who can un-block it.

  • 2

    Check browser extensions and parental controls

    Browser extensions (ad blockers, security tools, VPN extensions) can block specific sites. Open the site in Incognito/Private window (disables most extensions by default) → if it loads, an extension is the blocker → disable them one at a time to find it.

  • 3

    Check your hosts file for manual blocks

    Some software (and malware) adds entries to the hosts file to block domains. Open Notepad as Administrator → open the file at:

    C:\Windows\System32\drivers\etc\hosts

    Look for any lines pointing the blocked domain to 127.0.0.1. Delete those lines, save the file, and retest.

  • 4

    Request an exception from whoever controls the network

    If the block is network-level, only whoever controls the network can remove it.

    Work network: contact IT help desk with the exact URL + error message + a brief business justification — most teams process within a business day.

    Home network: log into your router's admin page → check content filtering/parental controls, or check your ISP account for opt-in site blocking.

  • 1

    Identify who is blocking the site

    The error tells you the source: "Your administrator has blocked this site" = browser policy or extension.

    A branded block page from Cisco Umbrella, Forcepoint, or Zscaler = corporate DNS filter/firewall. Open the same site on your phone's mobile data → if it loads fine, the block is on your office network, not your Mac.

  • 2

    Test in a Private window with extensions disabled

    Safari: ⌘⇧N → Private window (disables extensions by default). Chrome: ⌘⇧N → Incognito. If the site loads privately but not normally, an extension is the blocker → disable them one at a time via Safari → Settings → Extensions to find it.

  • 3

    Check your hosts file for manual blocks

    Some software/malware add entries to the hosts file redirecting domains to 127.0.0.1. Open Terminal → edit the file:

    sudo nano /etc/hosts

    Look for any line that maps the blocked domain to 127.0.0.1 or 0.0.0.0 and delete it. Press Ctrl+O to save, Ctrl+X to exit. Then flush the DNS cache:

    sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder
  • 4

    Request an exception from whoever controls the network

    If the block is network-level, no Mac setting bypasses it — only whoever controls the network can remove it.

    Work network: contact IT help desk with the exact URL + error message + a brief business justification — most teams process within a business day.

    Home network: log into your router's admin page → check content filtering/parental controls, or check your ISP account for opt-in site blocking.

  • 1

    Identify what's blocking the site

    # Test if it's a DNS block (resolves to wrong IP)
    nslookup blocked-site.com
    dig blocked-site.com

    # Test direct TCP connection bypassing DNS
    nc -zv blocked-site.com 443

    # Compare result with a different DNS resolver
    nslookup blocked-site.com 8.8.8.8
  • 2

    Test in a browser without extensions

    # Open Chrome/Chromium in incognito (no extensions)
    google-chrome --incognito https://blocked-site.com

    # Or open Firefox in safe mode
    firefox --safe-mode
  • 3

    Check the /etc/hosts file for manual blocks

    # Check if the domain is blocked in /etc/hosts
    grep blocked-site.com /etc/hosts

    # Edit the hosts file to remove any block entries
    sudo nano /etc/hosts

    Delete any line pointing the domain to 127.0.0.1 or 0.0.0.0 → flush DNS:

    sudo resolvectl flush-caches
  • 4

    Request an exception if blocked at network level

    Work network: if blocked by a corporate firewall/DNS filter (Cisco Umbrella, Zscaler, etc.) → contact IT help desk with the exact URL + nslookup output from step 1 + a brief business justification.

    Home network: check router admin page for content filtering, or ISP account for opt-in site blocking.

⚠️

Do not attempt to bypass corporate network blocks using a personal VPN on a company device. This violates most acceptable-use policies and could result in a security review of your device.

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Related Questions

Quick answers for this issue

It means a browser-level policy — usually set by a company's device management software (MDM) — is blocking the site at the Chrome or Edge policy level, separate from any network firewall. Only your IT administrator can change this policy; clearing cache or switching networks won't help.
No. Using a personal VPN to bypass corporate network blocks on a company device typically violates acceptable-use policies and can trigger a security review of the device. Request a formal exception from IT instead — it's faster and avoids any compliance issues.
Not quite — a certificate warning before a block page usually means your company uses an SSL inspection proxy that intercepts HTTPS traffic, and its certificate may be expired or untrusted on your device. This is closer to an authentication/certificate issue; see our Authentication Errors guide for the certificate troubleshooting step.
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Not sure who's blocking the site — or how to get it unblocked?

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Related

Website access trouble often overlaps with these.

🔌

App Not Connecting

The desktop app version is blocked too.

Fix it →
🔑

Authentication Errors

Certificate or TLS issues mistaken for a block.

Fix it →
🔒

VPN Keeps Disconnecting

Internal tools only reachable through VPN.

Fix it →
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