Could be due to huge number of audit files in node 1 (RAC1).
Please you let me know which operating system you are using.
if you are using linux or unix, check the mount point size where in your grid and database software is installed.
it should be 100% full which is causing this sqlplus hung issue.
My operating system is Linux 64 Bit. and all the mount points have sufficient space. There is no message in DB alert log/listener log.
Kindly advice me if i can check some else.
I have encountered this error, and the problem is about the DNS is wrong.
Please, check your network settings wheter is ok.