How to fix the Oracle error ORA-19166: FONS0003: FONS0004: no namespace found for prefix?

In this post, you’ll learn more about the Oracle ErrorORA-19166: FONS0003: FONS0004: no namespace found for prefix with the details on why you receive this error and the possible solution to fix it.

Oracle Error Description

ORA-19166: FONS0003: FONS0004: no namespace found for prefix

Reason for the Error ORA-19166: FONS0003: FONS0004: no namespace found for prefix

There was a zero-length URI in namespace declaration.

How to fix the Error ORA-19166: FONS0003: FONS0004: no namespace found for prefix ?

You can fix this error in Oracle by following the below steps

Fix the namespace declaration.