I am getting this error when trying to access content that I have found / retrieved within a global function.. The code is

using Microsoft.Extensions.DependencyInjection;
using MyWebsite.Config.Interfaces;
using MyWebsite.Models;
using Umbraco.Cms.Core;
using Umbraco.Cms.Core.Models.PublishedContent;
using Umbraco.Cms.Core.Services;
using Umbraco.Cms.Core.Web;
using Umbraco.Extensions;

namespace MyWebsite.Config
{
    public class GlobalConfiguration : IGlobalConfiguration
    {
        #region Private Properties

        private readonly IServiceProvider _serviceProvider;
        private readonly ServiceContext _serviceContext;
        private readonly IUmbracoContextFactory _umbracoContextFactory;
        private readonly IVariationContextAccessor _variationContextAccessor;

        #endregion

        #region Constructors

        public GlobalConfiguration(
            IServiceProvider serviceProvider,
            ServiceContext serviceContext,
            IUmbracoContextFactory umbracoContextFactory,
            IVariationContextAccessor variationContextAccessor
            )
        {
            _serviceProvider = serviceProvider;
            _serviceContext = serviceContext;
            _umbracoContextFactory = umbracoContextFactory;
            _variationContextAccessor = variationContextAccessor;
        }

        #endregion

        #region Email Template Methods

        public EmailChildTemplate? GetEmailChildTemplate(string templateAlias)
        {
            var currentCulture = Thread.CurrentThread.CurrentCulture;
            _variationContextAccessor.VariationContext = new VariationContext(currentCulture.Name);

            using var _ = _umbracoContextFactory.EnsureUmbracoContext();
            using var serviceScope = _serviceProvider.CreateScope();

            var query = serviceScope.ServiceProvider.GetRequiredService<IPublishedContentQuery>();

            var configSection = query.ContentAtRoot().First(t => t.IsDocumentType("configuration"));
            var emailTemplates = configSection.ChildrenForAllCultures.First(t => t.IsDocumentType("emailTemplates"));

            EmailChildTemplate? childTemplate = null;
            foreach (var emailTemplate in emailTemplates.ChildrenForAllCultures)
            {
                var myTemplate = emailTemplate.ChildrenForAllCultures.FirstOrDefault(t =>
                    t.GetProperty("emailTemplateAlias").GetValue().ToString() == templateAlias);

                if (myTemplate == null) continue;

                childTemplate = new EmailChildTemplate(myTemplate, new PublishedValueFallback(_serviceContext, _variationContextAccessor));
                break;
            }

            return childTemplate;
        }

        #endregion
    }
}

This seems to work and returns a valid "EmailChildTemplate".

However, where I am using it fails with the error "Wasn't possible to a get a valid Snapshot"

EmailChildTemplate? childTemplate = _globalConfiguration.GetEmailChildTemplate(templateAlias);
if (childTemplate == null) return null;

var rtnEmail = new EmailFields
{
    Send = true,
    SenderName = childTemplate.FromEmailName ?? string.Empty, <<== Fails here
    SenderEmail = childTemplate.FromEmailAddress ?? string.Empty,
    ReceiverEmail = childTemplate.ReceiverEmailAddress ?? string.Empty,
    Subject = childTemplate.SubjectLine ?? string.Empty,
    BccEmail = childTemplate.BCcemailAddress ?? string.Empty,
    CcEmail = childTemplate.CCemailAddress ?? string.Empty,
    PreHeader = childTemplate.Preheader ?? string.Empty,
    Headline = childTemplate.Headline ?? string.Empty
};

What am I doing wrong?