Check the log file at '/usr/local/flamenco/instances/ChEFS_-_19-09-06/log.txt' for more details. Here are the last few lines:
UseCascadingExtensions = 1
UserErrorMessage = The site is having technical difficulties with this page. An error has been logged, and the problem will be fixed as soon as possible. Sorry!
Loading context: default at /usr/local/flamenco/python
Current directory: /usr/local/flamenco/instances/ChEFS_-_19-09-06
Session Sweeper started
Plug-ins list: /usr/local/flamenco/webware/MiddleKit, /usr/local/flamenco/webware/MiscUtils, /usr/local/flamenco/webware/COMKit, /usr/local/flamenco/webware/TaskKit, /usr/local/flamenco/webware/UserKit, /usr/local/flamenco/webware/PSP, /usr/local/flamenco/webware/WebUtils
Loading plug-in: MiddleKit at /usr/local/flamenco/webware/MiddleKit
Loading context: MKBrowser at /usr/local/flamenco/instances/ChEFS_-_19-09-06/../../webware/MiddleKit/WebBrowser
Loading plug-in: MiscUtils at /usr/local/flamenco/webware/MiscUtils
Loading plug-in: COMKit at /usr/local/flamenco/webware/COMKit
Plug-in /usr/local/flamenco/webware/COMKit cannot be loaded because:
Required op sys is ['nt'], but actual op sys is posix.
Loading plug-in: TaskKit at /usr/local/flamenco/webware/TaskKit
Loading plug-in: UserKit at /usr/local/flamenco/webware/UserKit
Loading plug-in: PSP at /usr/local/flamenco/webware/PSP
Loading plug-in: WebUtils at /usr/local/flamenco/webware/WebUtils
Found an available port: 21600.
Listening on ('127.0.0.1', 21600)
Creating 10 threads..........
Ready (0.38 seconds after launch)