If you have login or account related issue, please check the following steps. The MKБ-10 server may be down and that is causing the login/account issue. Please try logging in after few minutes. Your wifi / mobile data connection not working properly. Please check your data connection. You may be trying with wrong login credentials. Please confirm the details that you are entering is correct. If you're using third-party social networks to login such as facebook, twitter, google etc, check whether that service is working properly by visiting their official website. Your account may be banned or deactivated for activities. Please read error messages.