SAP Message BDDISTMODEL071 - Message type & already exists in model view &

Diagnosis
A message type in connection with a client and a server can only bedefined in several model views, if the validity periods of the modelviews are disjunctive.
The message type &v1& is already defined for client &v3& and serverV4 in model view v2, whose validity periods overlap.

Procedure
Change the validity periods so that they do not overlap. Then try toadd the message type again.