Citrix Receiver 12.1 Issue: Cannot connect to server

Hello,

I am using MacBook Pro OS X EI Capitan Version 10.11.4. The Citrix Receiver 12.1 has been installed and it worked fine two days ago.

Since two days I've got following error message: Cannot connect to server “;40;STAxxxxxx". The network team confirmed that the Citrix Server & Network are ok, because another Citrix clients have not such issue.

Meanwhile I've uninstalled and reinstalled Citrix Receiver several times, but the issue cannot be fixed.

Any idea?

Thanks!