While attempting to access DBMS_LOB, the following error pops up:

ORA-00904: invalid identifier.

For example:

      SELECT dbms_lob.getlength(networkoriginalmessage) blob_len             *

The ORA-00904 error in conjunction with dbms_lob indicates that the execute privilege has not been granted to "PUBLIC" or has been revoked.

The execute priv on dbms_lob needs to be granted to PUBLIC or the individual user. Log into SQLPlus as sys as sysdba:

SQL> grant execute on dbms_lob to Public;

or

SQL> grant execute on dbms_lob to [user];