Error in MVC when create controller - Code First

Question

Hello

I Have Probelm When Create MVC APP code First

i create models and Context And Initializer, and Set Webconfig File

But When Create Controller i find this message

Error

There was an error running the selected code generator :

'unable to retrieve metadata for 'nameofApp.model.class'.

sections must only appear once per config file. see the help topic<location> for Exception.

(c:\users\nameofdevice\AppData\local\temp-mpCD0C.tmp line 20 )'