A couple of questions:
1) Are you using the final release of Visual Web Developer and ASP.NET 2.0 or Beta2.
2) Can you open your Windows event viewer and look under the "Application" event log. Everytime a failure occurs an audit event is added there by default. For example:
Event code: 4006
Event message: Membership credential verification failed.
Event time: 2/13/2006 11:30:41 AM
Event time (UTC): 2/13/2006 7:30:41 PM
Event ID: d048ad0365f24cf398d985985269aba3
Event sequence: 4
Event occurrence: 1
Event detail code: 0
Application information:
Application domain: 648db734-5-127843326127843001
Trust level: Full
Application Virtual Path: /simpledata
Application Path: E:\simpledata\
Machine name: SCOTTGU101
Process information:
Process ID: 3620
Process name: WebDev.WebServer.EXE
Account name: REDMOND\scottgu
Request information:
Request URL: http://localhost:34360/simpledata/Default6.aspx
Request path: /simpledata/Default6.aspx
User host address: 127.0.0.1
User:
Is authenticated: False
Authentication Type:
Thread account name: REDMOND\scottgu
Name to authenticate: ds
Custom event details:
For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
Can you check what this value is when your login fails and what the reasons are?
Thanks,
Scott