Challenge fails with Connection refused (challenge type http-01)

src/FluffySpoon.AspNet.LetsEncrypt/Certes/LetsEncryptOptions.cs

@@ -46,9 +46,9 @@ public class LetsEncryptOptions
 		/// </summary>
 		public RenewalFailMode RenewalFailMode { get; set; } = RenewalFailMode.LogAndContinue;
 
-        /// <summary>
-        /// Gets or sets the <see cref="Certes.KeyAlgorithm"/> used to request a new LetsEncrypt certificate.
-        /// </summary>
-        public KeyAlgorithm KeyAlgorithm { get; set; } = KeyAlgorithm.ES256;
+		/// <summary>
+		/// Gets or sets the <see cref="Certes.KeyAlgorithm"/> used to request a new LetsEncrypt certificate.
+		/// </summary>
+		public KeyAlgorithm KeyAlgorithm { get; set; } = KeyAlgorithm.ES256;
     }
 }

src/FluffySpoon.AspNet.LetsEncrypt/Certes/LetsEncryptRenewalService.cs

@@ -4,6 +4,7 @@
 using System.Threading;
 using System.Threading.Tasks;
 using FluffySpoon.AspNet.LetsEncrypt.Certificates;
+using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.Logging;
 using static FluffySpoon.AspNet.LetsEncrypt.Certificates.CertificateRenewalStatus;
 
@@ -14,6 +15,7 @@ public class LetsEncryptRenewalService : ILetsEncryptRenewalService
 		private readonly ICertificateProvider _certificateProvider;
 		private readonly IEnumerable<ICertificateRenewalLifecycleHook> _lifecycleHooks;
 		private readonly ILogger<ILetsEncryptRenewalService> _logger;
+		private readonly IApplicationLifetime _lifetime;
 		private readonly SemaphoreSlim _semaphoreSlim;
 		private readonly LetsEncryptOptions _options;
 
@@ -22,11 +24,13 @@ public class LetsEncryptRenewalService : ILetsEncryptRenewalService
 		public LetsEncryptRenewalService(
 			ICertificateProvider certificateProvider,
 			IEnumerable<ICertificateRenewalLifecycleHook> lifecycleHooks,
+			IApplicationLifetime lifetime,
 			ILogger<ILetsEncryptRenewalService> logger,
 			LetsEncryptOptions options)
 		{
 			_certificateProvider = certificateProvider;
 			_lifecycleHooks = lifecycleHooks;
+			_lifetime = lifetime;
 			_logger = logger;
 			_options = options;
 			_semaphoreSlim = new SemaphoreSlim(1);
@@ -45,10 +49,12 @@ public async Task StartAsync(CancellationToken cancellationToken)
 					" which means that the LetsEncrypt certificate will never renew.");
 			}
 
+			_lifetime.ApplicationStarted.Register(() => OnApplicationStarted(cancellationToken));
+
 			foreach (var lifecycleHook in _lifecycleHooks)
 				await lifecycleHook.OnStartAsync();
 
-			_timer = new Timer(async state => await RunOnceWithErrorHandlingAsync(), null, TimeSpan.Zero, TimeSpan.FromHours(1));
+			_timer = new Timer(async state => await RunOnceWithErrorHandlingAsync(), null, Timeout.InfiniteTimeSpan, TimeSpan.FromHours(1));
 		}
 
 		public async Task StopAsync(CancellationToken cancellationToken)
@@ -93,19 +99,22 @@ public async Task RunOnceAsync()
 
 		private async Task RunOnceWithErrorHandlingAsync()
 		{
-			try
-			{
+			try {
 				await RunOnceAsync();
 				_timer?.Change(TimeSpan.FromHours(1), TimeSpan.FromHours(1));
-			}
-			catch (Exception e) when (_options.RenewalFailMode != RenewalFailMode.Unhandled)
-			{
+			} catch (Exception e) when (_options.RenewalFailMode != RenewalFailMode.Unhandled) {
 				_logger.LogWarning(e, $"Exception occured renewing certificates: '{e.Message}.'");
-				if (_options.RenewalFailMode == RenewalFailMode.LogAndRetry)
+				if (_options.RenewalFailMode == RenewalFailMode.LogAndRetry) {
 					_timer?.Change(TimeSpan.FromMinutes(1), TimeSpan.FromMinutes(1));
+				}
 			}
 		}
 
+		private void OnApplicationStarted(CancellationToken t) {
+			_logger.LogInformation("Application started");
+			_timer?.Change(TimeSpan.Zero, TimeSpan.FromHours(1));
+		}
+
 		public void Dispose()
 		{
 			_timer?.Dispose();

src/FluffySpoon.AspNet.LetsEncrypt/RegistrationExtensions.cs

@@ -135,8 +135,9 @@ public static void AddFluffySpoonLetsEncrypt(
 			services.AddSingleton<ILetsEncryptClientFactory, LetsEncryptClientFactory>();
 			services.AddSingleton<ICertificateValidator, CertificateValidator>();
 			services.AddSingleton<ICertificateProvider, CertificateProvider>();
+
 			services.AddTransient<ILetsEncryptRenewalService, LetsEncryptRenewalService>();
-			services.AddTransient<IHostedService, LetsEncryptRenewalService>();
+			services.AddTransient<IHostedService, LetsEncryptRenewalService>();			
 		}
 
 		public static void UseFluffySpoonLetsEncrypt(