Message Oracle NNL-00015 - type string has string syntax, which has no textual representation

ERRORtype string has string syntax, which has no textual representation
CAUSENot all data type syntaxes can be represented as text. This message indicates that the user issued a name server request for a type with an non-textual representation.
ACTIONRe-issue the operation with a data type that has a syntax with a textual representation.