[SNAP Plugin] Error autoposter WP Blog

Hi all,

I’m using SNAP Plugin social bookmark autoposter Version: 2.7.18 [Single Accounts Edition] on my website https://3dprintersforsales.com

Then I fill autopost to WP Blog to https://3dprintersforsale.wordpress.com with XMLRPC https://3dprintersforsale.wordpress.com/xmlrpc.php

But when I click green button Submit test post to wordpress, a popup display with message “Testing …
Something went wrong – 500 : You are not allowed to do that.Something went wrong – 500 : You are not allowed to do that.”

My username and password to https://3dprintersforsale.wordpress.com are correct.
Wordpress.com version number 3.7-alpha-25157.

I asked to the SNAP Plugin developer and they said this error means that wordpress.com doesn’t like what are you doing for it’s internal reasons.

Please help me, thank you.
Best Regards