The default time for this trigger is every minute, since you haven't specified otherwise.
You can check all the intervals using this code:
var dt = trigger.GetNextFireTimeUtc();
for (int i = 0; i < 10; i++)
{
if (dt == null)
break;
Console.WriteLine(dt.Value.ToLocalTime());
dt = trigger.GetFireTimeAfter(dt);
}
If you want to schedule your job to run once a day at 5pm, you can change your code adding a 24 hour interval:
var trigger = TriggerBuilder.Create()
.WithIdentity("DailyReportTrigger")
.WithDailyTimeIntervalSchedule(s => s.OnEveryDay().StartingDailyAt(new TimeOfDay(timeOfExecution.Hours, timeOfExecution.Minutes)))
.WithIntervalInHours(24)
.Build();