I am getting below exception, when trying to insert a batch of rows to an existing table
ORA-00942: table or view does not exist
Is it possible that you are doing INSERT for VARCHAR but doing an INSERT then an UPDATE for CLOB?
INSERT
VARCHAR
UPDATE
CLOB
If so, you'll need to grant UPDATE permissions to the table in addition to INSERT.
See https://stackoverflow.com/a/64352414/1089967