DRAC: The maximum number of user sessions is reached.

how to solve this problem ?

login to ur server as root , and execute 

#racadm racreset

RAC reset operation initiated successfully. It may take up to a minute

for the RAC to come back online again.

wait for a moment till the DRAC is coming UP.

ORA-12547: TNS: lost contact

Stop listener nya

Startup the database first 

sqlplus / as sysdba

SQL> startup
sampai nongol "database mounted"

and then start the listener again.