Custom Content Importer & References

I’m writing a custom content importer, but mgcb fails to build the content when I try to use an external library/nuget package in my project.

For instance, if I try to use Newtonsoft.Json, the pipeline tool gives me an error when I try to build the content.

System.IO.FileNotFoundException: Could not load file or assembly ‘Newtonsoft.Json’

My library is .Net Core 3.1

Am I doing something wrong, or is it just not possible to reference other libraries?

The assembly Newtonsoft.Json.dll must be on the same folder that your importer is.
Naturally, all references will be on the bin folder when you build your importer. If you moved it, you need to copy the entire bin folder.