"Instead use {
<Or>Or<=Or>=Or> and <} so it can be converted into a SQL statement and run faster"
Some extension methods on DateTime such as IsBefore(...) and IsBetween(...) are not recognized by the LINQ to SQL converter in the database engine. So you should write the simpler alternatives using standard operators instead.
Database.GetList<LogonFailure>(f => f.Date.IsBefore(someDate));should be 🡻
Database.GetList<LogonFailure>(f => f.Date < someDate);