I was having an issue with permissions on one of my .NET applications. I added the following line to the webconfig and things started to go wrong.

```
<add key="authenticator.login_page" value="login.aspx" />

```

I took the line away, and now, cant login with any of my users. I tried adding users to Website/ASP.Net configuration and got the following error.

```
Login failed for user 'NT AUTHORITY\NETWORK SERVICE'

```

I gave this user permissions to the applications database, which got rid of the above error, but cant add users in Website/ASP.Net configuration anymore, 

```
Cannot open user default database. Login failed. Login failed for user 'HOST\user'. 

```

and the application is just showing our custom 'user cannot login' message.

Anyone know what I should look out for.

Mark