diff --git a/source/Octopus.Tentacle.Client/TentacleClient.cs b/source/Octopus.Tentacle.Client/TentacleClient.cs
index ad32af085..58b1f4580 100644
--- a/source/Octopus.Tentacle.Client/TentacleClient.cs
+++ b/source/Octopus.Tentacle.Client/TentacleClient.cs
@@ -37,8 +37,8 @@ public static void CacheServiceWasNotFoundResponseMessages(IHalibutRuntime halib
             var innerHandler = halibutRuntime.OverrideErrorResponseMessageCaching;
             halibutRuntime.OverrideErrorResponseMessageCaching = response =>
             {
-                if (BackwardsCompatibleCapabilitiesV2Helper.ExceptionTypeLooksLikeTheServiceWasNotFound(response.Error.HalibutErrorType) ||
-                    BackwardsCompatibleCapabilitiesV2Helper.ExceptionMessageLooksLikeTheServiceWasNotFound(response.Error.Message))
+                if (BackwardsCompatibleCapabilitiesV2Helper.ExceptionTypeLooksLikeTheServiceWasNotFound(response.Error!.HalibutErrorType!) ||
+                    BackwardsCompatibleCapabilitiesV2Helper.ExceptionMessageLooksLikeTheServiceWasNotFound(response.Error!.Message))
                 {
                     return true;
                 }
diff --git a/source/Octopus.Tentacle/Communications/TentacleCommunicationsModule.cs b/source/Octopus.Tentacle/Communications/TentacleCommunicationsModule.cs
index 1b3c3f114..efa17976e 100644
--- a/source/Octopus.Tentacle/Communications/TentacleCommunicationsModule.cs
+++ b/source/Octopus.Tentacle/Communications/TentacleCommunicationsModule.cs
@@ -36,7 +36,7 @@ protected override void Load(ContainerBuilder builder)
 
                 var halibutRuntime = new HalibutRuntimeBuilder()
                     .WithServiceFactory(services)
-                    .WithServerCertificate(configuration.TentacleCertificate)
+                    .WithServerCertificate(configuration.TentacleCertificate!)
                     .WithMessageSerializer(serializerBuilder => serializerBuilder.WithLegacyContractSupport())
                     .WithHalibutTimeoutsAndLimits(halibutTimeoutsAndLimits)
                     .Build();
diff --git a/source/Octopus.Tentacle/Configuration/ProxyConfigParser.cs b/source/Octopus.Tentacle/Configuration/ProxyConfigParser.cs
index 3c4ee0f23..8f4ac1e68 100644
--- a/source/Octopus.Tentacle/Configuration/ProxyConfigParser.cs
+++ b/source/Octopus.Tentacle/Configuration/ProxyConfigParser.cs
@@ -59,12 +59,12 @@ public class ProxyConfigParser : IProxyConfigParser
             {
                 log.Info($"Agent will use the octopus configured proxy at {config.CustomProxyHost}:{config.CustomProxyPort} for server at {destination}");
                 return string.IsNullOrWhiteSpace(config.CustomProxyUsername)
-                    ? new ProxyDetails(config.CustomProxyHost,
+                    ? new ProxyDetails(config.CustomProxyHost!,
                         config.CustomProxyPort,
                         ProxyType.HTTP,
                         null,
                         null) //Don't use default creds for custom proxy if user has not supplied any
-                    : new ProxyDetails(config.CustomProxyHost,
+                    : new ProxyDetails(config.CustomProxyHost!,
                         config.CustomProxyPort,
                         ProxyType.HTTP,
                         config.CustomProxyUsername,
diff --git a/source/Octopus.Tentacle/Services/FileTransfer/FileTransferService.cs b/source/Octopus.Tentacle/Services/FileTransfer/FileTransferService.cs
index fe92c1f92..1331a9174 100644
--- a/source/Octopus.Tentacle/Services/FileTransfer/FileTransferService.cs
+++ b/source/Octopus.Tentacle/Services/FileTransfer/FileTransferService.cs
@@ -60,7 +60,7 @@ public async Task<DataStream> DownloadFileAsync(string remotePath, CancellationT
 
         public async Task<UploadResult> UploadFileAsync(string remotePath, DataStream upload, CancellationToken cancellationToken)
         {
-            if (upload == null)
+            if (upload == null!)
             {
                 log.Trace("Client requested a file upload, but no content stream was provided.");
                 return new UploadResult(ResolvePath(remotePath), null!, 0);