I have looked around and there are a number of threads such as this such as this one which are similar but do not match exactly, so I figured I would start another thread just in case there are others out there.
While piloting Zscaler Client Connector/ZApp (herein ZCC) with our I.S. department, I received periodic complaints from remote users that Outlook would not connect to their mailbox to send/receive email. If you “Turn Off” ZCC, the problem will resolve itself immediately. And once Outlook and/or Teams has connected, you can turn ZCC back on and everything will work properly going forward. These are the only apps I have received complaints or noticed the issue. If I open up Excel or Word, I seem to be logged in/connected properly.
Unlike the link above, I DO NOT see tons of entries in the event logs indicating a problem. I have opened up a support ticket and the first round provided some subtle change(s) which may or may not have fixed the issue. It is hard saying since it is intermittant.
I am able to replicate the issue with a VMware VM running Windows on my MacBook, but this could also have something to do with the way things are networked from Fusion, so I am waiting to hear back from my testing pool. I would love to get this problem behind us so it doesn’t bite us as we roll out to 3,350 more users. So if anyone else has had this issue and has fixed it, I would love to hear how. We are only using ZIA right now. And this is with MS Teams and Outlook clients connecting to O365. It almost seems like the clients are unable to authenticate.
Thanks for your time -