For security reasons DTD is prohibited in this XML document. To enable DTD processing set the ProhibitDtd property on XmlReaderSettings to false and pass the settings into XmlReader.Create method.

In SSIS when we will create task where data source is XML source.

We may get a warning message like:

For security reasons DTD is prohibited in this XML document. To enable DTD processing set the ProhibitDtd property on XmlReaderSettings to false and pass the settings into XmlReader.Create method.

Cause: Your XML file also contains DTD (Document Type Definition).  

Solution: SSIS doesn't support DTD in XML file. So remove the all DTD from your XML file.