Warning: Error in as.character: cannot coerce type 'environment' to vector of type 'character'

[gausshuang]

shinyApp(ui=shinyUI, server=shinyServer)

Failed to open connection to "session" message bus: Using X11 for dbus-daemon autolaunch was disabled at compile time, set your DBUS_SESSION_BUS_ADDRESS instead
Running without a11y support!
Error: no DISPLAY environment variable specified
Warning: Error in as.character: cannot coerce type 'environment' to vector of type 'character'
[No stack trace available]