How to troubleshoot 'String could not be parsed as XML' error message in PHP

This article describes how to troubleshoot the "String could not be parsed as XML" error message in PHP.

Problem

When you try to parse XML data in a PHP script, you receive the following error message:

Fatal error: Uncaught exception 'Exception' with message 'String could not be parsed as XML' in FILENAME on line X

Resolution

The most likely cause of this error is that the XML data you are trying to process is not valid. Alternatively, the XML data may contain non-standard characters or use a different character set encoding.

There are several websites that can validate XML data. For example, the website http://www.xmlvalidation.com can check basic XML syntax, as well as validate XML data against external schema, such as DTD (Document Type Definition) documents.