go to  yoursiteroot/Secure.Login.aspx

Hope it helps,

Joe

Only solution is to fix it in the db

UPDATE mp_Sites

SET DisableDbAuth = 0

WHERE SiteID = 1

or if a multi site installation you need the siteid of the specific site.

After running the query you need to touch your Web.config file so it clears the Site Settings from cache.

Hope it helps,

Joe