After installing the Alloy tech demo site, I’ve run into this error a few times on my first install when trying to log into the editor.
1. Make sure you are using the right user-name and password. I have found that when I’m using my Windows account and there are no EPiServer users added, typing in a wrong username and password combo will cause this issue.
2. Switch to only using Windows Authentication. To fix the issue open your web.config in the [Configuration] ->EPiServer -> Web.Config and go to the ‘roleManager’ section. Change the role and membership provider to use the Windows versions, as below:
Reload the editor and everything should be fixed.
Now to make sure you don’t get the error again.. create an EPi admin user and change your settings back to how they were and stop using your Windows credentials 🙂