ORA-60555
Container cannot be changed in a local object
Cause
An attempt is being made to switch to another pluggable database (PDB) using a local procedure or begin-end block from inside the PDB. A local object inside a PDB cannot issue the ALTER SESSION SET CONTAINER statement. This is to prevent security issues.
Action
Use a common procedure from within the PDB to switch to another PDB or try any method while being connected to root.