We have a problem with the theme. When you try to login, or if you go to ‘my acount’, in both pages you can read this message: “Conected as %2$S. Logout?”
What is login ID, please provide in the private area. The login ID should be in Latin, perhaps you used other symbols which are not supported. Create the login in Latin letters only and try again.
Please deactivate all the plugins not related to the theme and switch the parent theme, check the issue, if the problem remains, leave the plugins not activated and provide the site admin access to the private area