Thanks for the answers. I wil do a restore Setup en configuration and hope that i got the replication task back.

The backup units holds now the Volume and is the source one.
De failed DSS (primary) is now destination. De data on the primary (failed DSS status destination) is not good so i must do a complete sync.
Where must i clear the metadata. On the backup unit where the volume is source or must i clear it on the failed one (primary) where the volume is destination.