I set my system up with the exact same as your code above. I get the same results. What I did to fix it was change your line
'rewrite' => array( 'slug' => 'articles', 'with_front' => true ),
to
'rewrite' => array( 'slug' => 'articles2', 'with_front' => true ),
and then to
'rewrite' => array( 'slug' => 'articlis', 'with_front' => true ),
and everything loaded fine on the last 2 options. It looks like maybe there is perhaps a built-in usage of articles already so that when you re-write to “articles” wordpress isn’t sure what to do. I don’t have an explanation for it.
What I would suggest all the same is use a CPT name more specific than what you are currently using.
Instead of articles, can you use a name that is actually what the post will represent? Changing