What causes the 'error message' when accessing links in emails and how can it be resolved?

Key findings

• Recipient-side factors: Many link access issues are localized to the recipient's device, network, or software (e.g., VPNs, corporate firewalls, antivirus, or ad-blocking software), not the email's sender. The email itself was likely delivered successfully.
• Linked domain reputation: Web security services, such as Cloudflare, may block access to a linked domain if the recipient's IP address or the domain itself is suspected of malicious activity or has a poor reputation, leading to Access Denied messages.
• Email service provider (ESP) redirects: Email marketing platforms often use tracking links that redirect through their own domains. If these intermediary domains (e.g., Marketo's click-tracking pages) encounter network or security blocks, the final destination URL cannot be reached. You can learn more about how email filters modify or break links.
• Browser and application settings: Incorrect browser settings, outdated default applications, or problematic extensions can prevent hyperlinks from functioning correctly within email clients like Outlook.
• Firewall and antivirus interference: Security software on a user's device or network can mistakenly flag legitimate links or the redirect domains as threats, preventing access.

Key considerations

• Isolate the issue: Determine if the link error is widespread or isolated to a single recipient or a specific network. Test the link from various devices and networks (e.g., personal phone data, different Wi-Fi networks).
• Check recipient's environment: Advise the recipient to try disabling any VPNs, checking their internet connection, temporarily disabling antivirus or ad-blocking software, or consulting their IT department if on a corporate network. You can also review how to fix tracking links not working in Chrome.
• Review linked domain reputation: If the problem persists across different recipient environments, investigate the reputation of the linked domain (or your ESP's tracking domain if used). Ensure it's not on any web blacklists (blocklists) or flagged for suspicious activity. Tools for troubleshooting broken links can be helpful.
• Check email client settings: For issues specifically within an email client like Outlook, advise the user to check their default browser settings and email client configurations to ensure hyperlinks are enabled and recognized correctly.

Key opinions

• Recipient network issue: A common opinion is that the recipient's internet connection, especially if it's a company network or VPN, often blocks access to certain external URLs or redirects, causing the error. For more on this, consider how to prevent Outlook from flagging email links as unsafe.
• Not a sender reputation issue: Many marketers agree that if the email successfully lands in the inbox and only the link is inaccessible, it's typically not related to the sender's IP or domain reputation. The email was delivered, but web access to the linked resource was blocked.
• ESP tracking links: Marketers recognize that email service providers often wrap original links with their own tracking domains. If these tracking domains or their underlying infrastructure (like Cloudflare) are flagged, it can lead to access issues even if the final destination is fine.
• Software interference: Ad-blocking software, antivirus programs, or internal PC settings are frequently cited as culprits for blocking web content, including links from emails. Addressing this requires direct troubleshooting on the recipient's machine.

Key considerations

• Engage IT support: When a link issue occurs within a corporate environment, it's often best to loop in the recipient's internal IT team. They have the tools and access to investigate network-level blocks or software conflicts. You can also explore how common email deliverability issues are resolved.
• Test multiple scenarios: Encourage the recipient to test the link on different devices (e.g., a personal phone on mobile data, a home Wi-Fi network) to pinpoint if the issue is device-specific, network-specific, or related to a corporate VPN.
• Understand link tracking: Marketers should be aware of how their ESPs handle link tracking, as the intermediary domain used for redirects might be the point of failure if it has a poor reputation. This is distinct from your sending IP reputation.
• Provide direct URLs: As a temporary workaround, or for critical communications, consider including a direct, untracked URL in the email body or a plain text version of the email to bypass any tracking domain issues, or even monitor your server status regularly.

Key opinions

• Cloudflare blocking: Experts identify Cloudflare as a common source of such blocks, often triggered when it detects access attempts from an IP address (the recipient's) with a poor or suspicious reputation. This means Cloudflare sees the IP trying to reach the website as potentially harmful.
• Recipient's IP reputation: The problem lies with the recipient's connection (IP, Wi-Fi network, or VPN) being flagged, not the sender's IP. The email successfully arrived, but the subsequent web request was blocked. Ensuring proper domain reputation is still vital for senders.
• Not a deliverability issue: A key point from experts is that if the email was delivered, the link error is a web access issue, not a deliverability one. It requires web-blocking troubleshooting, which differs significantly from email deliverability diagnostics.
• Local software interference: Antivirus, ad-blocking software, or other local security tools on the recipient's computer or phone can actively prevent links from opening, even legitimate ones. This requires investigation on the recipient's device.

Key considerations

• Diagnose the recipient's network: If a link error occurs, ask the recipient about their network connection (corporate Wi-Fi, home Wi-Fi, VPN usage) and if others on the same network experience the issue.
• Advise against personal VPNs: Experts suggest that personal VPNs can route traffic through suspicious IPs, leading to Cloudflare or other web firewalls blocking access. Advising the recipient to temporarily disable their VPN can help diagnose the problem.
• Involve internal IT: For corporate networks, the issue is typically a matter for the company's IT department to investigate web-blocking policies, firewalls, or network-level security. Understanding why Gmail might flag outbound links is a related topic.
• Check linked domain's web reputation: While not a sender IP issue, it's prudent to ensure the web domain being linked to doesn't have a poor web reputation that could trigger blocks by services like Cloudflare. Utilize tools to check the domain's web reputation.

Key findings

• Link protocol requirement: Many systems require web links in emails to explicitly begin with http:// or https:// protocols; otherwise, they might be broken or inaccessible after click tracking is applied.
• Default browser association: Operating system settings that incorrectly or incompletely register the default internet browser are a frequent cause of hyperlinks not working from email clients.
• System-wide security tools: Firewalls and antivirus software on the recipient's computer or network are known to block access to websites, causing This Site Can't Be Reached or similar errors.
• Email client settings: Misconfigured email application settings can prevent hyperlinks from being recognized and opened, sometimes requiring a reset of the application's internet settings.

Key considerations

• Verify link formatting: Ensure all links, especially custom ones or those with tracking, are correctly formed with the full protocol (http/https) to prevent parsing issues by email clients or tracking systems. This is also important for avoiding SpamAssassin hexadecimal sequence errors.
• Check email client defaults: Advise users to check and reset their default internet browser settings within their operating system and their email client to ensure correct link handling. You can also review why you get privacy errors from Gmail in Chrome.
• Troubleshoot firewall/antivirus: When a 'site can't be reached' error occurs, documentation suggests temporarily disabling antivirus software or firewalls to identify if they are the source of the block. Refer to resources like the Kinsta knowledge base for troubleshooting this error.
• Monitor server status: Regularly monitoring the status of the server hosting the linked content can help identify and resolve any server-side issues that might lead to broken or inaccessible links for recipients.