Quic Protocol Fails to Connect

Quic is a high-speed UDP protocol available in Windows 11 and Server 2022 and later operating systems. MFT 3 and later versions can use this protocol on systems where it is supported. This can significantly reduce transmission time for large files that are copied on networks with high latency.

If the source and destination operating systems support Quic, MFT will attempt to use the protocol. It will also use TCP on the same port number. There are cases where a connection via Quic are not possible and the system will fall back to using TCP.

The Server item in the Desktop program has an option to use Quic on system where it is supported. This is selected by default.

Quic connection attempts might get rejected internal with a System.Security.Authentication.AuthenticationException or "System.Net.Quic.QuicException: An internal error has occurred. ConfigurationLoadCredential failed: Unknown (0x80090331)". This would mean that there is an issue related to the security protocols required by Quic.

Quic requires the availability of TLS 1.3 or later. This would be on by default on the supported operating systems.

Quic also requires some cipher suites, which are also present by default. If you did an in-place operating system upgrade from an older operating system, these cipher suite may not be present. To check to see if the suites are present, use this PowerShell command:

Get-TlsCipherSuite | Where-Object Name -eq "TLS_AES_256_GCM_SHA384"

If nothing is displayed, it may mean the required cypher suite is blocked. But sometimes it just does not display.

To try to force adding the required cipher suites, use these PowerShell commands:

Enable-TlsCipherSuite -Name "TLS_AES_256_GCM_SHA384" -Position 0
Enable-TlsCipherSuite -Name "TLS_AES_128_GCM_SHA256" -Position 1

If the does not fix the problem, you need to use the local group policy to set the list of cypher suites. It might be best to copy these from a working system.