For years a new published wordpress article within hours would appear on Google Serps

Recently this isnt happening
Instead the author page or category page is being shown

The actual article page doesnt appear at all in the results


Can some one give me a clue as to how to fix this

I have checked the articles are all follow
Title and descriptions are fine
The xml sitemap is submitting to Google webmaster

I can only guess this must be a double content issue with the Author page and Category page taking the glory for a new article in the Serps

Is this correct?