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Hi
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
Using classic Outlook for Windows in business environments
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.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(48, 79%, 14%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EIM%3C/text%3E%3C/svg%3E)
I thought that this issue had been resolved, but we had this pop up again for several users this morning.
DigiCert Inc
Serial: 0f12dc8955821d6d936bcf34e50f60c5
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(54.400000000000006, 50%, 15%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3ESJ%3C/text%3E%3C/svg%3E)
Nope. Not resolved. Just got the Security Alert this morning.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(208, 65%, 30%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EW%3C/text%3E%3C/svg%3E)
Same here. Not fixed. Still got the Security Alert.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(281.6, 52%, 37%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EMG%3C/text%3E%3C/svg%3E)
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.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(32, 63%, 13%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EMS%3C/text%3E%3C/svg%3E)
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:
This only worked a short time, trying again with deleted registry keys.
