If you disconnect and reconnect a VMware Horizon session without logging out, the virtual channels stop working. The virtual channels are required for the SAM Terminal Server extensions to drive SuperNova's Speech and Braille.
Log out of the VMware Horizon active session and then log back in to re-establish speech and braille in SuperNova.
The issue has been identified in the "vdp_rdpvcbridge.dll", and we have informed VMware of the discovery, so we hope that a fix will be provided in a future release/update of VMware Horizon.