Fix Office Certificate Warning for incidents.diagnostics.office.com
Question details
The user is repeatedly receiving security certificate warnings indicating an untrusted certificate or a name mismatch for the domain incidents.diagnostics.office.com.
- Product
- Microsoft Office
- Device & OS
- not provided
- Scenario
- Opening Microsoft Office applications or Outlook, which triggers background diagnostic telemetry connections.
- Observed behavior
- A warning prompt appears stating the certificate for incidents.diagnostics.office.com is untrusted or its name does not match the website, despite the certificate expiration date being valid.
Ensure your computer's system time and date are completely accurate, as incorrect time settings are a common cause of invalid certificate warnings. You should also check if you are connected to a corporate VPN or proxy that might be inspecting secure web traffic.
Verify Network, Proxy, and DNS Configurations
Network inspection tools and incorrect DNS records often cause certificate name mismatch errors by intercepting traffic intended for Microsoft domains.
In many corporate environments, SSL inspection tools or strict firewall rules intercept traffic to Microsoft's diagnostic servers. When this happens, the Office application receives the firewall's certificate instead of Microsoft's, causing a mismatch error.
Right-click the clock in your taskbar, select 'Adjust date/time', and ensure 'Set time automatically' is turned on.
Temporarily disconnect from your corporate VPN or disable proxy settings in your Windows network properties to see if the warning disappears.
Open Command Prompt as an administrator, type 'ipconfig /flushdns', and press Enter to clear outdated or incorrect DNS records.
If you are on a corporate network, report the issue to your IT team. They may need to update firewall SSL inspection whitelists or fix DNS resolution for Microsoft endpoints.
Inspect the Certificate Chain
Viewing the specific certificate details helps identify exactly which layer of the certificate chain is failing or replacing the original Microsoft certificate.
Try WPS Office for a Warning-Free Experience
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- 1. Download WPS Office: Visit the official WPS website and download the free installation package for your operating system.
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Frequently Asked Questions
Why does incidents.diagnostics.office.com trigger a certificate error?
This domain is used by Microsoft Office for diagnostic and telemetry data collection. If your network's DNS routes it incorrectly, or if a firewall intercepts the traffic without issuing a properly trusted certificate, the Office client detects a mismatch and displays a warning.
Can I just click 'Yes' to proceed past the certificate warning?
While clicking 'Yes' may allow the application to connect temporarily, the warning will likely return the next time the software runs a diagnostic check. It is safer to resolve the underlying network or proxy issue than to continually bypass security warnings.
Does this warning mean my computer has a virus?
No, a certificate name mismatch is usually caused by network misconfigurations, captive portals, or corporate SSL inspection tools rather than malware.
How do I stop Microsoft Office from connecting to diagnostic servers?
You can minimize these connections by disabling optional connected experiences. In an Office app, navigate to File > Account > Account Privacy > Manage Settings, and uncheck the options for optional diagnostic data.
