First, download and install the updated version of the software and uninstall (Control Panel > Uninstall a program) the previous one. After that, navigate to Start > Control Panel > System and Security > Windows Firewall > Allow a program through Windows Firewall and check the box next to Tuitalker. If you can't find the application in the Allowed programs and features window, press the Allow another program button, navigate to the installation directory, select the executable file and press Add. Next, 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. Also, check if your security program doesn't block the Tuitalker connection. If the problem persists, it's possible that the Tuitalker servers to be temporarily down or other maintenance. In this case you will need to wait.