1. Sign up the user with a "space" sign in user name (for ex, "New Year")
2. Sign in.
3. Press "Profile" button
As a result, 404 error has been shown.
4. Create any topic.
5. Click on user name of "author" of the topic.
As a result, 404 error has been shown.

The same error appears when trying to view the profile by clicking on user name on the main page, on the page with the list of branches, on the page with the list of topics, on the topic page.