I came across this problem very recently while trying to deploy a working product to a new server. There's more information in this StackOverflow question I posted, but here's a summary.
When you do a date comparison with DateTime.Now using LINQ-to-Entities against a SQL Server database, the engine translates DateTime.Now to GetDate().
var items = (from t in context.Token where t.Expiry > DateTime.Now).ToList();
will ultimately generate SQL that says:
... WHERE Token.Expiry > GetDate() ...
This can cause some significant (and subtle) problems:
If the application running this code is on a different server to the SQL database, any time differences can break code.
This is what happened to me. There was a one minute time difference between the web service running this code and the SQL Server machine. I was using the Entity Framework to set the expiry date to DateTime.Now.AddSeconds(60), and retrieving it later by comparing it to DateTime.Now. Despite this, I was effectively setting the expiry using the web server's time, and comparing it using the SQL Server's time.
If you're having a similar problem, I hope you stumble across this post.