Microsoft Site Showing Warning Following Certificate Expiry

Cybersecuritynews •Guru Baran • June 15, 2026

Microsoft seems to have failed certificate management after a domain used by sysadmins globally to test connectivity to Microsoft 365 started generating untrusted connection warnings in browsers on Monday. The connectivity.office.com domain a widely relied-upon tool for IT professionals to verify their network’s connectivity to Microsoft 365 and confirm that firewalls aren’t silently blocking critical […]

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Microsoft Connectivity Domain Faces Trust Issues After Certificate Expiry Microsoft's connectivity.office.com domain, used by IT professionals to test access to Microsoft 365, began displaying untrusted connection warnings after its TLS certificate expired on June 14, 2026. The certificate had not been renewed for over 35 hours at the time of reporting, raising concerns about Microsoft's certificate management practices. The expired certificate resulted in NET::ERR_CERT_DATE_INVALID errors, affecting users attempting to validate network access. Although the situation is irritating for users, it is not catastrophic compared to potential issues with critical services like login.microsoft.com. Microsoft has been contacted for a response but had not provided one by the time of publication. The incident highlights the importance of timely certificate renewals, especially as SSL/TLS certificate lifespans are set to decrease in the coming years. 5 sources 37

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Domains (1)

connectivity.office.com