@Fakhri
Just to be sure: The formula is to be used on Text property, right?
I've updated the formula to be:
If( DateDiff((scheduledend),Now(),Minutes)<60 , Concatenate(Text(DateDiff((scheduledend),Now(),Minutes))," mins ago"),
DateDiff((scheduledend),Now(),Hours)<=24 , Concatenate(Text(DateDiff((scheduledend),Now(),Hours))," hours ago"),
DateDiff((scheduledend),Now(),Days)<=31 , Text(scheduledend),,
DateDiff((scheduledend),Now(),Months)<=12 , Concatenate(Text(DateDiff((scheduledend),Now(),Months))," months ago"),
Concatenate(Text(DateDiff((scheduledend),Now(),Years))," years ago"))
But that returns a series of errors. Could this be a copy/paste error?

The formula I use (which I hope to ditch) looks like this:
Text(scheduledend, DateTimeFormat.LongDate)
Which results in this:
Monday, October 1, 2018