Currently experiencing the above errors more often than I'd like on our setup but I'm not sure what's causing them. We have a relatively small number of people using thin clients to login to VMs and they're all dedicated, so it's 1 user to 1 VM (no floating) Occasionally a user reporting this on looking on View-Connection will already be logged in and I imagine are therefore blocking themselves from logging in as the system already thinks they are logged in.
Let me know if you need anymore info to go on:
ESXI v5.5 -
Vcenrer V 6.0.0
Viewsecurity v 5.3.1
Viewcomposer V 5.3.1