RMAN delete obsolete error RMAN-10003 ORA-01005

Error RMAN-10003 ORA-01005:

% rman target /

Recovery Manager: Release 11.2.0.3.0 - Production on Sun Aug 09 09:03:51 2015

...

connected to target database: ORCL (DBID=1234567890)

RMAN> delete obsolete;

RMAN-00571: ===========================================================

RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============

RMAN-00571: ===========================================================

RMAN-03002: failure of crosscheck command at 08/09/2015 09:03:52

RMAN-12001: could not open channel ORA_DISK_1

RMAN-10008: could not create channel context

RMAN-10003: unable to connect to target database

ORA-01005: null password given; logon denied

Solution:

RMAN> CONFIGURE CHANNEL 1 DEVICE TYPE DISK CLEAR;