Hi there, I have an install of Umbraco (7.4.3) on a stage and live environment and was using Courier (2.52.7) to sync between the two successfuly. However, the servers have been locked down to only TLS1.2 and now I get the below error when trying to sync:

System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a receive. ---> System.ComponentModel.Win32Exception: The client and server cannot communicate, because they do not possess a common algorithm
at System.Net.SSPIWrapper.AcquireCredentialsHandle(SSPIInterface SecModule, String package, CredentialUse intent, SecureCredential scc)
at System.Net.Security.SecureChannel.AcquireCredentialsHandle(CredentialUse credUsage, SecureCredential& secureCredential)
at System.Net.Security.SecureChannel.AcquireClientCredentials(Byte[]& thumbPrint)
at System.Net.Security.SecureChannel.GenerateToken(Byte[] input, Int32 offset, Int32 count, Byte[]& output)
at System.Net.Security.SecureChannel.NextMessage(Byte[] incoming, Int32 offset, Int32 count)
at System.Net.Security.SslState.StartSendBlob(Byte[] incoming, Int32 count, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Net.TlsStream.ProcessAuthentication(LazyAsyncResult result)
at System.Net.TlsStream.Write(Byte[] buffer, Int32 offset, Int32 size)
at System.Net.ConnectStream.WriteHeaders(Boolean async)

Has anyone come accross this before as i've been going around in circles for weeks!?

Thanks

J

------------ UPDATE --------------

We believe that this might be a .Net problem with version 4.6 using TLS1.2. The MS page here has some information around it: https://support.microsoft.com/en-gb/kb/3069494 They recommend adding this to the website::

Programmatically: Must be the very first thing the application does because ServicePointManager will initialize only once. Use the following code example in your application:
private const string DisableCachingName = @"TestSwitch.LocalAppContext.DisableCaching";
        private const string DontEnableSchUseStrongCryptoName = @"Switch.System.Net.DontEnableSchUseStrongCrypto";
        AppContext.SetSwitch(DisableCachingName, true);
        AppContext.SetSwitch(DontEnableSchUseStrongCryptoName, true);
By using the AppConfig file for your application: Add the following line to the Appconfig file:
<AppContextSwitchOverrides value="Switch.System.Net.DontEnableSchUseStrongCrypto=true"/>

Where would I add this in an Umbraco install?

Many thanks