Unable to resolve service for type 'IRepository' while attempting to activate 'Controller'

I have been trying to follow a tutorial on Pluralsight. I can't get past the first step because the example project I am using is getting the following error:

Unable to resolve service for type 'CrestSSODemo.API.Services.IGalleryRepository' while attempting to activate 'CrestSSODemo.API.Controllers.ImagesController'.

I have looked through a fair few Stack Overflow forums that come up when I search this error code, but I can't find one that helps. I see a lot about checking that the Program.cs file needs the IRepository to be scoped (AddScoped), or to check that my Controller constructor has the "I" on the Repository interface in the parameters. I have done these checks and cannot find what I am doing wrong.

I have an "API" project which contains my "Services" folder which contains the "IGalleryRepository" interface and the "GalleryRepository" implementation. Then in the ImageController, in the Controllers folder of the same project, I can't resolve the GalleryRepository services. I have the Repositories scoped in the API Program.cs file, and the correct "using" in the ImagesController.cs.

Here is my code:

Program.cs

using CrestSSODemo.API.Services;
using CrestSSODemo.API.DbContexts;
using Microsoft.EntityFrameworkCore;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.

builder.Services.AddControllers()
    .AddJsonOptions(configure => configure.JsonSerializerOptions.PropertyNamingPolicy = null);

builder.Services.AddDbContext<CrestGalleryContext>(options =>
{
    options.UseSqlite(
        builder.Configuration["ConnectionStrings:ConnectionString"]);
});

// register the repository
builder.Services.AddScoped<IGalleryRepository, GalleryRepository>();

// register AutoMapper-related services
builder.Services.AddAutoMapper(AppDomain.CurrentDomain.GetAssemblies());

var app = builder.Build();

// Configure the HTTP request pipeline.

app.UseHttpsRedirection();

app.UseStaticFiles();

app.UseAuthorization();

app.MapControllers();

app.Run();

ImageController.cs

using AutoMapper;
using CrestSSODemo.API.Services;
using CrestSSODemo.Model;
using Microsoft.AspNetCore.Mvc;

namespace CrestSSODemo.API.Controllers
{
    [Route("api/images")]
    [ApiController]
    public class ImagesController : ControllerBase
    {
        private readonly IGalleryRepository _galleryRepository;
        private readonly IWebHostEnvironment _hostingEnvironment;
        private readonly IMapper _mapper;

        public ImagesController(IGalleryRepository galleryRepository, IWebHostEnvironment hostingEnvironment, IMapper mapper)
        {
            _galleryRepository = galleryRepository;
            _hostingEnvironment = hostingEnvironment;
            _mapper = mapper;
        }

        [HttpGet()]
        public async Task<ActionResult<IEnumerable<Image>>> GetImages()
        {
            // get from repo
            var imagesFromRepo = await _galleryRepository.GetImagesAsync();

            // map to model
            var imagesToReturn = _mapper.Map<IEnumerable<Image>>(imagesFromRepo);

            // return
            return Ok(imagesToReturn);
        }
    }
}

Edit: GalleryRepository.cs

using CrestSSODemo.API.DbContexts;
using CrestSSODemo.API.Entities;
using Microsoft.EntityFrameworkCore;

namespace CrestSSODemo.API.Services
{
    public class GalleryRepository : IGalleryRepository
    {
        private readonly CrestGalleryContext _context;

        public GalleryRepository(CrestGalleryContext galleryContext)
        {
            _context = galleryContext ??
                throw new ArgumentNullException(nameof(galleryContext));
        }

        public async Task<bool> ImageExistsAsync(Guid id)
        {
            return await _context.Images.AnyAsync(i => i.Id == id);
        }

        public async Task<Image?> GetImageAsync(Guid id)
        {
            return await _context.Images.FirstOrDefaultAsync(i => i.Id == id);
        }

        public async Task<IEnumerable<Image>> GetImagesAsync()
        {
            return await _context.Images
                .OrderBy(i => i.Title).ToListAsync();
        }

        public async Task<bool> IsImageOwnerAsync(Guid id, string ownerId)
        {
            return await _context.Images
                .AnyAsync(i => i.Id == id && i.OwnerId == ownerId);
        }

        public void AddImage(Image image)
        {
            _context.Images.Add(image);
        }

        public void UpdateImage(Image image)
        {
            // no code in this implementation
        }

        public void DeleteImage(Image image)
        {
            _context.Images.Remove(image);

            // Note: in a real-life scenario, the image itself potentially should 
            // be removed from disk.  We don't do this in this demo
            // scenario to allow for easier testing / re-running the code
        }

        public async Task<bool> SaveChangesAsync()
        {
            return (await _context.SaveChangesAsync() >= 0);
        }
    }
}

Any help would be greatly appreciated, if you need more information/code please let me know and I will add it to the question as an edit.

Thanks in advance!

Turns out the problem was that the port number was wrong in the URL of the API root in the Client project appsettings.json. Therefore, it couldn't find the API, therefore could not resolve the interface. I had to change the port number/URL (I was using localhost) to match the one setup in the API project appsettings.json under ApplicationUrl.