Could not convert Base64 string to XString content. Check the source file

What causes this issue?

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

System Response

How to fix this error?

INCLUDE NA_SYSADMIN1 OBJECT DOKU ID TX

Procedure for System Administrators

Contact the partner that made the source file available, and make sure
that the file is correct.

Error message extract from SAP system. Copyright SAP SE.