Variable [date] in name of archive: Error

Hello

I hope you can help me, because I couldn't find anything about this error. In the documentation it is described how to use the variable [date] in the name of an archive.
So I created a new backup plan, chose my personal depot and the name: MyArchive-[DATE]

And there is the error: the name of the backup archiv contains a [date] variable, which can't be used for the specified location.

I tried this with several locations; local, the personal depot, a network folder, always the same error.
I don't get it, according to the documentation, this should work...

Can anyone help me?

I'm using Acronis Backup & Recovery 11.5...

Thanks...