Oracle Message EXP-00104 - datatype (string) of column string in table string.string is not supported, table will not be exported

ERRORdatatype (string) of column string in table string.string is not supported, table will not be exported
CAUSEThe column is of a datatype which does not contain the required support. The table will not be exported.
ACTIONUse the Data Pump version of Export to export this table.