Cannot implicitly Convert type

Question

I am in error in instantiating the service. It is generic and I need it so, because I can use any entity in it. When I start the service in Hibernate, I need to pass the entity I will work to use the bank mapping. That is, when I install the service passing Tipodocumento or Document, it uses the mapping of the entity Tipodocumento or Document. I will only use methods and properties of the parent entity, I just need to use the daughter class to access the mapping of the right table that I will search. on normal screens, I overwrite the methods passing the entity I need, but on the search screen, I need to do everything on the same screen, because it is impossible to make a screen for each search

Cannot implicitly Convert type 'Servicocadastromestre' to 'Servicocadastro'

public class TipoDocumento : CadastroMestre
{
}

public class ServicoCadastroMestre<T> : ServicoCadastro<T> where T : CadastroMestre
{
}

public abstract class ViewCadastroMestre<T> : ViewCadastro<T> where T : CadastroMestre
{
    public abstract ServicoCadastro<T> GetServico();

    public abstract T GetEntidade();
}

public class ViewPesquisa : ViewCadastroMestre<CadastroMestre>
{
    public override CadastroMestre GetEntidade()
    {
        return new TipoDocumento();
    }

////o problema está aqui    
public override ServicoCadastro<CadastroMestre> GetServico()
    {
        return new ServicoCadastroMestre<TipoDocumento>();
    }
}

///////aqui funciona normalmente///////
public class ViewTipoDocumento : ViewCadastroMestre<TipoDocumento>
{
    public override TipoDocumento GetEntidade()
    {
        return new TipoDocumento();
    }
 
    public override ServicoCadastro<TipoDocumento> GetServico()
    {
        return new ServicoCadastroMestre<TipoDocumento>();
    }
}