Impossibile risolvere il servizio con ambito DbContextOptions

Ho cercato ora una risposta chiara su questo problema, incluso github e ancora non riesco a vedere cosa mi manca qui:

Impossibile risolvere il servizio con ambito ' Microsoft.EntityFrameworkCore.DbContextOptions`1 [PureGateway.Data.GatewayContext] ' dal provider principale.

In Startup.cs:

        public void ConfigureServices(IServiceCollection services)
        {
            //other code omitted for brevity

            var connection = Configuration.GetConnectionString("DefaultConnection");
            services.AddDbContext<GatewayContext>(options => options.UseSqlServer(connection));
            services.AddDbContextPool<GatewayContext>(options => options.UseSqlServer(connection));
            services.AddScoped<IGatewayRepository, GatewayRepository>();
        }

Uso:

public sealed class MatchBrokerRouteMiddleware
{
    private readonly RequestDelegate _next;
    private readonly ILogger<MatchBrokerRouteMiddleware> _logger;

    public MatchBrokerRouteMiddleware(
        RequestDelegate next,
        ILoggerFactory loggerFactory)
    {
        _next = next;
        _logger = loggerFactory.CreateLogger<MatchBrokerRouteMiddleware>();
    }

    public async Task Invoke(HttpContext context, GatewayContext gatewayContext)
    {
            await _next(context);
    }

Sto usando netcore 2.2.