DLL could not be found in D365FO project

Hi,

I built a dll called FirmaElectronica but when I try to use it with "using FirmaElectronica;" in a D35FO project I get this error message: The type or namespace name 'FirmaElectronica' could not be found (are you missing a using directive or an assembly reference?).

I've tried many things including:

Adding the dll to the bin folder of my D365FO project and then selecting from that path into the references.

Selecting the dll from the original dll project into the references.

Checking the compatibility of the .NET version from the dll with the .NET version of my D365FO project.

Checking that it is written the same as the namespace from the dll project.

The dll project compiles just fine without errors.

I built every model in the environment as well as synchronizing with the database.

I don't know what else I can do. Please help.

Thanks.