Running standalone vRO appliance, version 8.0.1.
Attempting to log in to http://vro_fqdn/orchestration-ui, received the following error:
The issue appears to be related to the standalone vRO appliance date/time not being properly time sync'ed.
See also... vCenter 6.7U2 / VRO 7.6 Orchestrator Client SSO Issue
vRO appliance has a command-line tool 'vracli', which has an argument to enable/disable time sync.
Run 'vracli ntp -h' to get a list of possible options.