Hello there! I am having difficulties with displaying avatars assigned to the members.

 <div class="coaches-carousel">
            @if (coachesList.Count() > 0)
            {
                foreach (var coach in coachesList.Where(itm => itm.GetValue<bool>("wwunavailable") == false))
                {
                    if (coach.GetValue<string>("wwavatar").IsNumeric())
                    {
                        mediaItemId = Convert.ToInt32(coach.GetValue<string>("wwavatar"));
                    }
                    else if (!string.IsNullOrEmpty(coach.GetValue<string>("wwavatar")))
                    {
                        mediaItemId = coach.GetValue<string>("wwavatar").GetIdByUdi();
                    }

                    <div class="coaches-carousel-item">
                        <a href="#">
                            <img src="@Umbraco.TypedMedia(mediaItemId).GetCropUrl("coach")" alt="@coach.Name" />
                        </a>
                    </div>
                }
            }
        </div>

Exception Details: System.ArgumentNullException: Value cannot be null. Parameter name: mediaItem

Any idea how I can display them?