How to dial on a single campaign across multiple Asterisk

im trying to make work this feature, but im not sure how to do it.
i register the secondary server on the primary server, i add the phones of the secondary server... and even add the conferences of the secondary server...
im able to iniciate a sesion but the phone doesnt rings...
could anyone explainme how make this work?
i register the secondary server on the primary server, i add the phones of the secondary server... and even add the conferences of the secondary server...
im able to iniciate a sesion but the phone doesnt rings...
could anyone explainme how make this work?