It looks like DTLS1 is broken from version 2108 and higher (at least when running on MacOS 11.5.x and higher). Removing the newer version of the Citrix Workspace app for Mac and re-installing version 2107 resolved this. In our case the app simply crashes after a few seconds when connecting via our Citrix Gateway on NetScaler 13.0 build 82.45 with DTLS1 enabled. We had similar issues after upgrading MacOS to Big Sur 11.5.2 and using any version newer than 2107 of the Citrix Workspace app for Mac.
