Before_install is not allowed


I’getting this error message when trying to install a new swarm service in my server:

before_install Additional property before_install is not allowed

I used same script as I did for the other 8 services that are currently running, but now i get this error and I do not know why.

Please, could you help me?
I’m using swarm version 3

Thank you

Forget it !!
It was a silly error from my side…