Log In Issues - Login is currently being used on a different browser

That error occurs when your username is signed in on one device, and then the same credentials are used to login on another device.  This typically happens if multiple people are using the same login details (which is not allowed under ESdat's terms and conditions), but could also happen if you have ESdat open in multiple browsers.  

To fix this, you will need to enable the multi-factor authentication (rather than skipping it).  With multi-factor authentication ESdat will ask you to register with an authenticator app, or receive an email code, which you will enter when logging in.  This means that any other devices that have saved credentials will no longer be able to log in without another uniquely generated code.  You should also ensure no one else is using your login.