Re: RMAN backups of HP-UX dedicated storage node fail with error "Dedicated storage node leda2 cannot save remote data from client cora127n1.melkweg.tld"
As you know Dedicated Storage Node (DSN) is used to store local data ( the client the storage node is attaches to) . So ensure firstly you have seperate licenses for DSN.
Secondly ensure that all the dns and hosts files ( name resolution ) is working well.
Also make sure that aliases are set properly, May be there is a mismatch where same box is seen as different one may be because it is multihomed or hostname not translated to FQDN.