RMAN failed to connect target database with ORA-00020: maximum number of processes (150) exceeded
Here, we can see in error as maximum number of processes has exceeded.
So, we need to Increase the number of processes from sys user with sysdba privilege which may help here as shown below:
SQL> show parameter processes;
NAME TYPE VALUE
——————— ———– ———
processes integer 150
SQL> alter system set processes=300 scope=spfile;
Bounce the database so changes will be reflected in database instance and then you can initiate RMAN backup.