Outlook Disconnection Over ZApp

We have recently deployed Zscaler App to multiple locations. And have started receiving complains of outlook disconnection, stuck on trying to connect etc when ZApp is ON. The same works when it’s turned OFF. We have the Office 365 one click enabled, Common Office 365 Applications exempted from SSL inspection.
Could someone advise what we can perform/troubleshoot to take care of this.


What mode is Zscaler App using to forward traffic?


Tunnel with local proxy


Do you have ticket open for this? Can you reference it here so we can look.
Additionally, there is a switch in the App Profiles for Z App for “Restart WinHTTP Service”, if this is set to ON, can you try turning this off. The reason is that we use the WinINET proxy settings, but Office applications will look at the WinHTTP proxy settings first. If this service is unavailable (potentially because Z App is configured to restart it), it can cause slowness on outlook startup while it waits for this.



Hi David,
Indeed i raised a case: 646045. We do have this option enabled: Restart WinHTTP Service. I’ll try turning this OFF and will check.
Hope this will not make issues or downtime as it’s live in production.

Just to add, the below is our current setup.
Forwarding Profile:

  • Tunnel with local proxy
  • A custom pac file.

App Profile:

  • Added a custom pac file.
    Install SSL Cert: Checked
    Disable Loopback Restriction: Checked
    Override WPAD: Checked
    Restart WinHTTP service: Checked

Did turning off Restart WinHTTP Service solve your dissonnect with outlook, thick client?

how did you solve this please?

Hi David,

Even to one of our customer facing same issue.
Case number : 982251

“Restart WinHTTP Service” is in OFF, using Tunnel with local proxy.

Can you please help me here.


Hi Atul,

Even to one of our customer facing same issue.

“Restart WinHTTP Service” is in OFF, using Tunnel with local proxy.

Can you please let me know is the issue is resolved ? If yes then what is the solution.

Hi all

We have the same issue now.
Is there any solution for this topic?

BR Daniel

are you using tunnel with local proxy mode?
try adding explicit statement in proxy pac file to send login.microsoftonline.com to zscaler IP or $gateway.

Hello community,

I am Georgios. Recently, we deployed ZPA in my company and this is still on POV (proof of value) phase. We are receiving complains from users having the same exactly issue. Frequent disconnects from Outlook and skype.

Is there any formal solution that has been proposed from a zscaler engineer as a fix for that?

That is happening to both macOS and windows machines. There is no difference while it is on tunnel or tunnel with local proxy.

I am not convinced that it is a configuration problem or it is simply a zscaler problem.

Thank you in advance,

Hi Everyone,

There’s a few issues that we’ve seen over time that can cause the same symptoms.
What would really help us is if you can list some particulars, most importantly which Z App you are running. If you’ve got a ticket open please paste the number in here and we can check that also.

Troubleshooting these issues usually requires logs and a lot of your specific data, so it’s generally better for these issues to go through support.