Cannot create simplenews content
I have tested on Drupal vanilla installation 7.50 and simplenews version 7.x-1.1 stable release, the link works perfect to add simplenews nodes.

I would recommend you

 -  Re install simplenews module
 -  Check if you see simplenews content type under structure&gt;&gt;content types
 -  Check if you see any error in your error logs.
 -  Check if you are using dev version of simplenews module