Cant add ASPNET login to SQL Server

Here's the situation:

SQL Server is on one machine.
ASP.net is running on a different machine named THALES, which has the ASPNET account on it.
Both machines are on the same domain.

I am trying to add the THALES\ASPNET as a SQL Server login so that I can connect using Windows Authentication. When I try to add THALES\ASPNET, I get this message:
Error 15401: Windows NT user or group 'THALES\ASPNET' not found. Check the name again.

Any suggestions?You need to create an ASPNET user on the SQL Server machine, and give it the same password as the ASPNET user on the Web Server. By default, the password for the ASPNET user is autogenerated. You will need to change this in the Machin.Config so that it is a known password that you can then use for the ASPNET user on the SQL Server machine.|||Thank you, Douglas, that helped.