Oracle Message ORA-19669 - proxy copy functions cannot be run on DISK channel

ERRORproxy copy functions cannot be run on DISK channel
CAUSEA proxy copy procedure was called, but the device which is allocated to the current session has type DISK.
ACTIONAllocate a non-DISK channel and retry the operation. Note that proxy copy requires a 3rd-party media management software product that supports the this backup/restore feature.