The type or namespace name 'Optimization' does not exist in the namespace 'System.Web'

Question

I am deploying a new website as my main site and it works beautifully.

All of my applications under the root url work as well, except for one. It is a legacy system (c#

Answer 1

I just faced this issue now:

I reinstalled the optimization framework and everything worked fine:

Install-Package Microsoft.AspNet.Web.Optimization