Cloudflare DNS Cert Warning showing in Outlook?


#1

Hi,

Could anybody provide some advice on the following:

I have a client who is getting intermittent warning popups in Outlook about the following cert:

Can anyone why this is happening, client is using Exchange via Office 365, by way of Telstra. Name servers of the domain don’t point to cloudflare name servers.


#2

What are they connecting to that’s giving them the SSL certificate for Cloudflare’s DNS website?


#3

cloudflare-dns.com is issued for 1.1.1.1./1.0.0.1. But it shouldn’t throw a warning. What’s the exact error message?


#4

So to clarify what @sdayman asked, thats the question :slight_smile: I don’t know either, so I’m not sure how to go about troubleshooting it. I have never encountered it before.

@MarkMeyer the dialogue box prior to the other screenshot already shared is:

Seeing that one, and the other one together (they were sent days apart) makes it a lot clearer to me. But I still don’t understand why that Office 365 cert is ultimately issued by Cloudflare? Is this a local network ‘issue’ or something domain side?

Thank you both for taking the time to reply to my initial post.


#5

Yes, but the URL is incomplete so there’s no screenshot. Look at your first post. :wink:

Cloudflare doesn’t issue certificates for Microsoft. I am not sure but it seems that there
is something messed locally. Do they use 1.1.1.1/1.0.0.1 as DNS servers? but even then they shoud not get this warnung.


#6

Not sure how that markup made its way into my post, i’ve edited the post. But its just the two screenshots, there is not a 3rd.

What I might do is try and replicate the issue on a different network/computer.

The unusual thing is that the certificate cannot be saved/installed either, but this may just be the end user’s computer literacy at play.

I’ve also just noticed Cloudflare has released a consumer DNS service. Does Cloudflare have any deals with antivirus or VPN software that would change the user/network’s DNS as a security/performance feature?

I will check to see what DNS the computers are using.