The member with identity '' does not exist in the metadata collection?

I could not figure out how to solve this problem between my base and my mapping using Fluent API.

I have a mapping in the Fluent API of a certain pre-existing table in the client database, however this table has a trigger that is triggered at insert / update time in>, every time I run my insertion test it gives the error reported in the title.

I've tried this:

Configuration.ValidateOnSaveEnabled = false; 

But it did not work.