Errors on login

I`m using code from your old examples:

var msgFactory = new OpenApiMessagesFactory();

var authMsg = msgFactory.CreateAppAuthorizationRequest(_clientId, _clientSecret);
await SendAndWaitForMessage(_apiSocket, authMsg);

var authAccMsg = msgFactory.CreateAccAuthorizationRequest(token, (long) _accountId);
var response = await SendAndWaitForMessage(_apiSocket, authAccMsg);

When sending SendAndWaitForMessage of authAccMsg I`m getting error:

"An established connection was aborted by the software in your host machine."

This error started to popup few days ago. Before this time everything was working fine I didnt change my sourcecode.