Evernote Android-job not getting triggered periodically

Question

I have a task which should be triggered periodically every 15 mins once it is scheduled. Below given is the code I use,

int jobId = new JobRequest.Builder(WallpaperJob.TAG)
        .setPeriodic(TimeUnit.MINUTES.toMillis(15), TimeUnit.MINUTES.toMillis(5))
        .setPersisted(true)
        .setUpdateCurrent(true)
        .build()
        .schedule();

I tried changing the phone date and time but it does not get triggered,I hope it is supposed to be triggered with respect to changes in system time. I cannot completely deny the job being triggered because at certain times I have noticed the job to have been taken place;but I am not sure of the interval.