Make sure you're logged out (logout button is at the top the of homepage), and then go to mod.learntomod.com which will automatically direct you to http://login-thoughtstem.herokuapp.com/
Then click the 'Can't Access Your Account' link in the Log in window. This will send a new password to to your LTM login email -- if that email is a dummy account or has a typo in it, email contact@learntomod.com so they can update your email to one you have access to. (We don't keep record of passwords).