Certificate Issue: sec_error_ocsp_invalid_signing_cert

[Corrine]

If you are seeing the error message below when attempting to access Microsoft services, it is in the process of being fixed. Although the Office 365 Service Status is only showing Outlook and now Yammer as affected by the OCSP issue, OneDrive Bing and other services have also been inpacted. Following is the current status:

User Impact: Users may be unable to connect to Outlook.com via the Mozilla Firefox browser.

More info: This is an incremental update to provide the latest status on the issue.
Current status: We've completed restarting over 70 percent of the affected systems and we anticipate that impact will be remediated by 3:00 AM UTC on June 1, 2017. Users will continue to experience service restoration as the certificate data is refreshed across the environment. For complete details on this event, please reference the Restoring service post from 12:55 AM UTC on May 30th, 2017.
Estimated restoration time: By Thursday, June 1, 2017, at 3:00 AM UTC
Next update by: Wednesday, May 31, 2017, at 12:00 AM UTC

Although the report only indicates Firefox, the OCSP issue has also affected Pale Moon as well as IE. It is also not limited to Windows users and has impacted Linux users as well.

Error Message:

Secure Connection Failed

An error occurred during a connection to outlook.live.com.

Invalid OCSP signing certificate in OCSP response.

(Error code: sec_error_ocsp_invalid_signing_cert)

The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.
Please contact the website owners to inform them of this problem.