System.Net.Sockets.SocketException in ForwardedPortLocal.StartPort

I have a piece of code that more or less does this:

var forwardedPort = new ForwardedPortLocal("127.0.0.1", (uint)boundPort, "127.0.0.1", (uint)port);

SshClient?.AddForwardedPort(forwardedPort);

forwardedPort.Start();

I often get this exception:

System.Net.Sockets.SocketException (0x80004005): An attempt was made to access a socket in a way forbidden by its access permissions
at System.Net.Sockets.Socket.DoBind(EndPoint endPointSnapshot, SocketAddress socketAddress)
at System.Net.Sockets.Socket.Bind(EndPoint localEP)
at Renci.SshNet.ForwardedPortLocal.InternalStart()
at Renci.SshNet.ForwardedPortLocal.StartPort()

I wonder if there's anything that I could be doing wrong (doesn't seem at first sight) or if there's anything else going on.
Thanks

Start with the ForwardedPortLocal.StartPort() and InternalStart() stack frames, then reproduce the bind using the shown ForwardedPortLocal setup. Determine whether the failure comes from the requested local endpoint or library behavior; done means documenting the cause and providing a verified fix or regression test.