Microsoft Website Displays Security Warning After Certificate Expiry

Gbhackers •Divya • June 16, 2026

Microsoft has triggered widespread browser security warnings after allowing the TLS certificate for a critical Microsoft 365 connectivity testing domain to expire, raising concerns over certificate lifecycle management practices. The affected domain, connectivity.office.com, widely used by system administrators and enterprise IT teams to validate network access to Microsoft 365 services, began returning NET::ERR_CERT_DATE_INVALID errors in […]

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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

Extracted Entities

Domains (1)

connectivity.office.com