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.

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-Asli 11 Reputation points

2022-10-28T14:00:36.043+00:00

We are having the same issue on a few systems in our environment as well.

The security certificate revoked error pop-up occurs at random times for on-premises users and remote VPN users (VPN is configured to split-tunnel mode).

As per Microsoft support, we updated the Outlook client to version 2202 and created new outlook profiles, but the pop-up still occurs. Time is also synced.

Yesterday the error started popping up on my machine several times as well.

So far, we can see this error only for SSL certificate from Digicert Cloud Services CA-1 with serial number: 0f12dc8955821d6d936bcf34e50f60c5 that is currently used by outlook.office365.com
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Chris Robb 21 Reputation points

2022-10-28T14:53:46.33+00:00

We're hearing reports of this for on-premise users of M365 starting this morning. we use Fortinet Fortigate firewalls, wondering if this is a certificate inspection issue with an outdated or incorrect CRL list.

Chris
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Mike C 1 Reputation point

2022-10-28T15:56:47.98+00:00

Same issue for many of our users using Outlook client and iOS so far. It is impacting both intranet and internet remote workers so is not Firewall specific.

Don't trust Microsoft to get certificates 100% right 100% of the time - by preventing 10% of users from connecting randomly they increase capacity by 10%!
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Cameron R 6 Reputation points

2022-10-28T19:55:05.29+00:00

I own an IT company and several of my customers are reporting this to me across the board. Some running AD sync and some not. Not all of the mailboxes for each domain experience this, only some. This has been happening since yesterday. There is no way this is related to anything other than a Microsoft issue itself. Does Microsoft reply to this or see this stuff or I wonder how many people have reported this by now.
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B_Toronto 26 Reputation points

2022-10-29T12:03:36.003+00:00

I have opened a ticket with Microsoft on this, just curious are the client seeing this error utilizing BitDefender?

I suspect this is a Microsoft issue this time, but can always be related to IPS inspection of firewalls or IPS/Deep-SSL or web protection from Antivirus products.

However we have seen a spike in these issues (never encountered previously) in the past two days.

Cameron R 6 Reputation points

2022-10-31T13:53:12.643+00:00

have you heard anything back from Microsoft yet? and btw, yes I'm using BitDefender and now i'm ALSO getting this message in my Outlook client now too. If I click on OK, messages start to download again... I went ahead and installed the certficate and going to see if it happens again but why hasn't Microsoft addressed this globally yet, this is obviously a very wide-spread problem.

B_Toronto 26 Reputation points

2022-10-31T14:54:22.21+00:00

Still waiting to speak to a higher-level engineer and Microsoft.

Thus far support blamed us for not having DNS setup correctly, not recognizing that we operate a Hybrid environment and have done so for 6 years before these issues started cropping up.

Also had ridiculous claims that as an example our MX records which point to a secure mail gateway are contributing, when auto-discover has nothing to do with MX.

In any case, still waiting to have an escalated call. The reason I asked about BD is there is always the potential that the webprotection module which uses SSL deep inspection could have been interfering with the certificates.

I haven't had an opportunity yet on an occurrence, rather than approving the cert to disable web protection in BD temporarily and see if that resolve the issue.

This is the only outside possibility.
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Chris Robb 21 Reputation points

2022-10-31T15:07:29.443+00:00

Following Friday morning we have not had any further occurrences with any of our clients. No issue today either.

I don't think this can be classified as anything to do with Bitdefender as we dont' use that product anywhere in our own stack but were experiencing the same issue.

@B_Toronto your support experience sounds exhausting. Hope you brought your patience! So frustrating that you gotten taken down a rabbit hole with MX records etc. This is very clearly a certificate revocation issue related to an MS cert. If there was a name mismatch I could see going down the path of a configuration issue. I really have to wonder if there is a certificate somewhere in the certificate chain of trust that was revoked, even temporarily or that some UTM products didn't like during SSL inspection and flagged as not trusted. I'm not 100% ready to blame MS on this one as I think Digicert, some root certificate, or even UTM products performing SSL inspection could be the cause.

Glad it isn't an issue today for us, but I don't like unsolved mysteries.

Chris
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security certificate revoked - outlook.office365.com

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