alter system archive log current hangs

Hello,

I have 2 instances (archive mode) in a cluster environment and after a backup fail, I realize I have problems with redo/archive files/process.

 Last instruction I can read on backup log:   alter system archive log current

 After stopping the backup I tried to execute this instruction using sqlplus but most of the times the instruction hangs.

 I used alter system switch logfile; so many times as groups I have but just one time I could finished the instruction alter system archive log current

 I tried to shutdown the instance but only shutdown abort works, shutdown immediate hangs every time I tried to use it.