Hi,
this is a very strange behavior, I have see that url of each member is something like http://domain.com/username, this is possible when you have a menu item of type Easy Profile->User Profile as Home page.
But from the HTML code of your site the Home Page should be a menu item of type K2.

If this is so then how you manage to use user profile URL like http://domain.com/username (without any other menu alias)?

Have you created a menu item of type Easy Profile->User Profile? If not then please create it.
Instead, If you already have this menu item then it is set as Home Page?

I have a Users » User Profile menu item which is not set as home page. I do not have a Easy Profile->User Profile menu item. This works well on my other site. I use Joomla and Moodle on my site. It seems like if this works well on my other site it would work well on the broken site. Are you suggesting that I replace the Users » User Profile menu item with a Easy Profile->User Profile menu item? I need to ensure all the fields that I use will show.

Hi,
to works correctly and avoid conflicts then you need to create a menu item of type Easy Profile->User Profile, you can create it in a hidden menu. This menu item require to have public access.

Hi,
can you please post me your site access? if yes then you can use the form below the reply in "Site Details" tab

Here it is.

Hi,
can you please give me backend rights?
Also...from frontend login does not works, I get error "ERR_TOO_MANY_REDIRECTS"

Hi,
sorry for late, I have found and fixed the problem.

This is due to plugin called "Easy Profile - Hits Plugin" (https://www.easy-profile.com/support/analytics-for-site-members.html).

This plugin require that after installation you need to open plugin settings and set the numeric field, the field parameter was empty.

This plugin increment hits value once for each session, so the error comes only first time you that you open the profile page.