zoom client switchs between proxy and firewall

Hi all,

We have a strange issue.

We use Zoom client for team chats.

All users in organization are behind proxy server and we have special rules for Zoom so that the proxy doesn't do SSL termination.

The issue is with images and screenshots in team chats - everything works fine for most users but for some, they can't send pictures and they get the gray exclamation mark and errors when sending or receiving pitcures.

We noticed that for users with errors, when sending/receiving pictures only, the client go through the corporate firewall (and gets blocked) and for users who have no issue, all traffic go through proxy without problem.

Anyone had such an issue?