In order to fix the issue, make sure your security program and Windows firewall doesn't block the connection. Also, go to Start, type Windows Firewall and Advanced Security and open the utility. From the Advanced Settings select Inbound Rules > New Rule. Check the Port box, click Next, select All local Ports and follow the self-explained steps. If it doesn't work, try uninstalling the application and then installing it again. Also, it is possible that the MXit servers to be temporarily down or under maintenance.