We added the horribly undocumented
#DEBHELPER# magic token to postinst in r16051, that seems to populate the file with lots of automatically generated sections, but our own sections are nowhere to be found now. In particular the ssl cert which was added in r14029.
This means that the cert is missing and we can't start the system wide proxy server (#1521) on Debian / Ubuntu.
So when trying to start a session it will print a warning that the system wide proxy server failed to answer and will fallback to "normal" start mode.
Here's the warning message:
Warning: cannot use the system proxy for 'start' subcommand, CONNECTION_LOST
this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/1721