The example configuration as code snippet for the schedule build plugin halts my Jenkins instance during startup. The example is:

unclassified:
  scheduleBuild:
    defaultScheduleTime: 23:00:00
    timeZone: Europe/Paris

The configuration as code errors report that timeZone cannot be used as a map.

Any use of defaultScheduleTime seems to cause Jenkins startup to halt with an error. If I start Jenkins with a working configuration like:

unclassified:
  scheduleBuild:
    timeZone: "America/Denver"

then the configuration as code "View configuration" will show the following segment:

unclassified:
  scheduleBuild:
    defaultScheduleTime: "10:00:00 PM"
    timeZone: "America/Denver"

However, if I save that configuration and restart Jenkins, the Jenkins startup process will halt.

I've not found any format of defaultScheduleTime that will allow Jenkins to start.