How to authorize users with the same name in Wordpress?

Question

CMS

Made a custom registration in wordpress by mail. It registers and logs in perfectly, but if you register 2 users with the same name, it does not authorize on the site. wp_signon() does not throw errors as such. But what should be is not working. Where is the check whether the user is authorized or not? in what place to look for and edit approximately?

Answer 1

Make it so that there are NOT users with the same name. This is complete nonsense. Login must be unique.