Browserstack and proxy requirement

We are using browserstack to test applications against various browser versions.,
what we discovered is that once we installed ZCC client and tried access internet via the client, browserstack is not working again and the error is " local testing is not enabled. if you are behind a proxy… configure your browser settings.
switching back to normal VPN,. this works well.
also firewall control has been setup to allow destination to * and SSL bypass configured but still not working

we are not using pac file

has anyone experienced this before and how did you address it