ORA-03135: connection lost contact when duplicating from active database always on system tablespace

Hi Folks,

I'm trying to  create a standby database (RAC 11GR2 to RAC11GR2) using duplicate from active database but I'm getting the error ORA-03135: connection lost contact. I don't know if its a coincidence (I don't think so) the erros always occurs when system tablespace is in copy process.

RMAN Command

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run {

allocate channel c1 type disk;

allocate channel c2 type disk;

allocate channel c3 type disk;

allocate channel c4 type disk;

allocate channel c5 type disk;

allocate channel c6 type disk;

allocate channel c7 type disk;

allocate channel c8 type disk;

allocate channel c9 type disk;

allocate channel c10 type disk;