It's grammatically sound, but the message doesn't quite make sense. If the elevator 'has been repaired', this means that it is OK again now. If you want to inform people that that the elevator isn't broken any more and they can use it, you might write "Please be informed that the elevator HAS NOW BEEN repaired." [Present Perfect Passive for a recently completed action] What I suspect you want to say is that the elevator is broken, and that people can't use it. Is that what you mean? If so, you should write "Please be informed that currently the elevator IS BEING repaired." This means that the mechanic is fixing it at the moment. [Present Continuous/Progressive Passive for an action happening at the moment].

We kindly Inform you that the Elevator are currently Repaired