How to solve Unable to locate factory with name [default] [App\Models\Domain]?

I'm trying to add a Factory to help increment my test coverage on some controllers. I've been using Factories with no issues till now, where I find no reason for this message and I can't figure out what is different from the rest of the factories, which are working perfectly.

The error is:

1) GuestBusinessControllerTest::it_presents_a_domain_home
InvalidArgumentException: Unable to locate factory with name [default] [App\Models\Domain].

In order not to make a never-ending post of code crap, I reference the useful files as follows:

• My Controller Test trying to use the Factory (Through a trait): GuestBusinessControllerTest
• The trait using the factory
• The factory definition
• I'm using "laracasts/testdummy": "~2.0"

Sidenotes:

Yes, I did composer dump-autoload (Else, the error message would be different)

I tried to define the factory in another helper file, and dump-autoload. (Just in case)

I also tried renaming my model, thinking that Domain might be a conflicting keyword, but that seems not to be the issue.

How may I solve this error?