Open your article and choose
Printer "PDF-XChange".
⇒ Settings
⇒ General
⇒ Conform to Specification → PDF/A-1b (RGB)
Name your article in the way, that it can easily be identified.
do not use dots other than file extension, or special characters (~ ! @ # $ % ^ & * ( ) ` ; < > ? , [ ] { } ' " | )