Create SQL Server Login for IIS APPPOOL – IIS and SQL Server on different machines

I’ve searched thoroughly- apologies in advance if I am missing an obvious answer.
Followed the recommendations at link below and the solution did not work. The solution also does not indicate whether it applies to a production webserver running IIS and SQL Server on separate computers.
Add IIS 7 AppPool Identities as SQL Server Logons

the best way to connect sql server (Windows authentication vs SQL Server authentication) for asp.net app

I have a database and a site having forms authentication. It is working fine with VS2008. This time, I am using “Trusted_connection =True”. But when it is opened from outside or directly from browser then I am getting error “Login failed for user ‘NT AUTHORITYANONYMOUS LOGON’.”