right click on (local) click "delete sql server registration" click "ok"
Right click on SQL Server Group select "New sql server registration" a wizard will popup. enter the netname of the sub and click next. Register the server using sql and windows authentication. enter the sa password and click finish. You should see the sql server register successfully. Then stop and restart the sql server agent service on the sub,
Replication should then be restored.
g'luck
James