idoc problem

Hi ConcernGood Morning

I am having certain problem while creating a distribution Model with a message type Matmas

It is giving me error "Message type MATMAS already exists in model view"

Is it giving becoz the same messaege type is dfinened in any of the the distributiontion model having the same sender or reciever(ie the logical system)

or for any Distribution Model.

How to Overcome this.