You need a Disqus shortname to enable Disqus comments on your blogs in your website. (Note that having a Disqus username is not enough)
Whats a Disqus shortname?
A Disqus shortname is a unique identifier assigned to a Disqus site. All the comments posted to a site are referenced with the shortname. The shortname tells Disqus to load only your site’s comments, as well as the settings specified in your Disqus admin. (taken from the Disqus website)
Click here for more information on what a Disqus shortname is, and how to get one.
How to get a Disqus Shortname?
You need to register your website with Disqus.
You can do that by clicking here: https://disqus.com/admin/signup/.
In the next step, you would specify your Disqus shortname. This is the same as your unique Disqus URL
Copy the shortname you have specified in this step in your Disqus registration.
Then go to the Settings section in Pixpa Studio and enter it here and save your settings.
Voila..you can now enable Disqus comments on any Blog you make in your website.