IDoc cannot be sent to an XML port

What causes this issue?

The IDoc should be sent to an XML port. However, as the IDoc has syntax
errors, it is not posible.
Only IDocs with correct syntax can be sent to XML ports as an XML
browser can only recognize and display these.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Procedure for System Administrators

Notify your system administration.

Error message extract from SAP system. Copyright SAP SE.