Connection error using SIM Card

Hi all,
since a few days we have some issues around the world when our users need to use their SIM Cards.
ZCC is not able to establish a connection towards the ZCloud.
This issue is with different SIM Card providers from Germany, Italy etc.
We figured out, if you use the SIM Card in another Notebook, the issue is following the SIM Card.

In Germany we also discovered if some users are customer of Deutsche Telekom and using the new Router from Telekom there is a feature called LTE Bonding, something like “lite SDWAN”. The LTE and WAN connection are used simultaneously. If you disable this feature, everything is working fine.

We already have multipe open Tickets with Zscaler but no resulution.

Is anyone else facing similar issues when using the SIM Card connection in a Notebook and maybe have a fix/solution/workaround?

Cheers Jonas

Hi Jonas,

Did you get to the bottom of this? We have a similar issue with a German sim card.

Kind regards,


Are you running ZTunnel2.0? If yes it is due to DTLS settings. If you switch them to TLS it is working fine.

Unfortunately until now I haven’t received any feedback from Zscaler why this is happening. Support case is open since months with no update…

Hi, I will check the end user. I am personally running Tunnel 2.0 TLS so would expect the end user to be the same.

Thanks for replying.