security certificate revoked - outlook.office365.com

John Rovel Kalaw 6

The pictures below started popping up on our PCs. and the PC was using not part of any domain. I tried to follow the link below but the IE was inaccessible. https://answers.microsoft.com/en-us/outlook_com/forum/all/outlookoffice365com-security-certificate-has-been/743bdb2b-06ce-4206-923e-bdb7041528bd

Drifter 1 Reputation point

2022-10-08T18:50:23.963+00:00

I am not a computer person and also have this problem. I clicked into the Security Alert message's "View Certificate" button and saw that the certificate is issued to "outlook.com" while the security message said the internet address "outlook.office365.com" has security concern. That to me essentially is a Microsoft mess up by using Peter's credential to do business as Paul.

I think that I started to have this pop up issue around when the new certificate became effective, that was 7/25/2022.

As to some PCs/Macs don't have the issue maybe because they already have the correct security certificate installed on their computers. There is no setting in my hotmail setup for me to change in Outlook, so so far I am dealing with it by clicking ok on the box everyday.

49 answers

Megan Gee 1 Reputation point

2022-11-28T14:08:32.47+00:00

MS had us do the below and one of our IT team members confirmed no pop ups for him since doing it. Been about 3-4 days...

Anyone else try this?

I hope my email finds you well! Regarding the issue the Service Incident EX455084 is resolved and if users are still facing the same,

please try in Outlook OST file location to check if there are any CML files with Autodiscover in their name and delete them.

Also, in registry HKCU\Software\Software\Microsoft\Office\16.0\Outlook\Autodiscover, check if there are any "Redirect Servers" if so, delete all except the default.

And in command prompt please run "ipconfig/flushdns". If issue still persist, create a new profile.
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M.Sqrl 1 Reputation point

2022-12-31T18:22:06.987+00:00

MS had us do the below and one of our IT team members confirmed no pop ups for him since doing it. Been about 3-4 days...
Anyone else try this?
> I hope my email finds you well! Regarding the issue the Service Incident EX455084 is resolved and if users are still facing the same,
> please try in Outlook OST file location to check if there are any CML files with Autodiscover in their name and delete them.
> Also, in registry HKCU\Software\Software\Microsoft\Office\16.0\Outlook\Autodiscover, check if there are any "Redirect Servers" if so, delete all except the default.
> And in command prompt please run "ipconfig/flushdns". If issue still persist, create a new profile.

I tried this just now and relaunched Outlook with no pop-up.
However, I need to clarify your instructions for those with limited expertise:

Outlook OST is found in "<drive>:\Users\<user>\AppData\Local\Microsoft\Outlook"; rename the .xml to .old; there are no "CML" files

I had a folder in Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoDiscover\RedirectServers which contained 5 items; (Software\Software\ does not exist; I did not delete them)

Win+R to bring up "Run", Run "cmd.exe", at command prompt type "ipconfig /flushdns"; space between not optional

This only worked a short time, trying again with deleted registry keys.
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Wendy 1 Reputation point

2022-11-22T14:22:15.493+00:00

Same here. Not fixed. Still got the Security Alert.
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Schuemacher, John 1 Reputation point

2022-11-22T12:08:48.7+00:00

Nope. Not resolved. Just got the Security Alert this morning.
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Iain McMullen 1 Reputation point

2022-11-21T16:46:30.747+00:00

I thought that this issue had been resolved, but we had this pop up again for several users this morning.
DigiCert Inc
Serial: 0f12dc8955821d6d936bcf34e50f60c5
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Wendy 1 Reputation point

2022-11-08T15:07:04.797+00:00

Any solutions from MS?
Same thing happens in our tenant, already created a case on MS support, no answer from the case owner so far.
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Tim 6 Reputation points

2022-11-14T14:14:06.077+00:00

According to MS this is fixed now, but better just monitor and see

Final status: Our analysis of the Outlook client diagnostic and memory process logs identified a subset of network infrastructure that processes Transport Layer Security (TLS) requests wasn't functioning as expect, resulting in impact. We've disabled this problematic network path, allowing traffic to flow through alternate routes and remediating impact.

Root cause: A subset of network infrastructure that processes TLS requests wasn't functioning as expect, resulting in impact.
Next steps:

We're identifying methods of bolstering the reliability of TLS infrastructure to prevent similar impact from occurring in the future.

We're analyzing our findings from this event's investigation to improve our network infrastructure monitoring to more quickly detect and address issues of this nature.

This is the final update for the event.

Daniel 1 Reputation point

2022-11-14T14:19:58.857+00:00

Thank you, Tim, for pursuing this with Microsoft, and sharing the answer from Microsoft as to the solution!
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