troubleshooting Question

Kaspersky blocks Outlook

Avatar of Hello There
Hello There asked on
OutlookVPNSecuritySSL / HTTPS
15 Comments1 Solution7939 ViewsLast Modified:
Hello everybody who wants to help me.

I have a bigger issue with my VPN client and Outlook running on one of them.
Let me describe it. And please, be patient.

Well, I have a computer connected to my company network via VPN. Few days ago I got a report that Outlook does not receive any emails. They were able to access the mail only using browsers but not via MS Outlook. It was weird because I did not do any changes within my VPN computers.

Settings for this PC: The connection to the Internet is disabled for all by Kaspersky Endpoint Security for Windows 10 (managed by Kaspersky Security Center from DC), except webmail and a few webpages needed for the work.

So I took this PC to my office for testing (now it was connected to local network).
1. Reinstallation of the KES didn't solve it.
2. When I turned off Kaspersky Endpoint Security, PC gains full access to the Internet (because the Kaspersky policy became inactive) and everything was OK and Outlook ran. But we need the Kaspersky working so this is not a solution.
3. When the all policies were on I was able to access the mail via name of the server in browser (mail-server/) but not via IP address of the server (all pings were successfull and I could log in via server name) - also weird. Outlook didn't work.
4. I also noticed that if I use the name of mail server, it automatically switched into insecure http page and I could log in to the mail but if I used an IP address, it switched into secure https mode and I was unable to login to the mail.
Considering this I denied the 443 port in Kaspersky and surprisingly the Outlook, mail via IP and mail via server name were all working.
So I put the PC to the remote location via VPN and guess what happened! Nothing because it wasn't working (the port 443 was denied). I was able to get into the mail only via an IP in browser again but not via Outlook.

So I took a spare PC and tried the same thing with the same settings and the result was ... exactly the same. So it is not an issue of the specific computer.

I think it is an Kaspersky issue. I've found several articles with this problem but with no real solution.

Could you please help me with this problem?

Well, there is one thing you should know. Windows GPO doesn't apply via VPN (I am solving this in another article). But there shouldn't be a real problem because it contains only password policy and this: see the attachment.

But I am not really sure if the Kaspersky applies its policy. Then the problem could be there.

Hello ThereSystem Administrator
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