If the connection suddenly failed which did not usually have any problems, there can be reasons as follows.
1. Circuit failure
If the internet circuit suddenly did not work or the condition is not good, you can connect to the server after the circuit is restored.
2. If the program is not updated
When you run the program after a long time, if the program automatic update is not activated, you cannot connect to the server. You can click the Download button and install the program again.
3. Incorrect password
As for password, capital letters and small letters are recognized differently. If the “Caps Lock” key is on when you enter your password, your password is changed to capital letters. If your password consists of small letters, you should turn off “Caps Lock.”
There can either be a high-level firewall that you set up on your personal computer or a company firewall in case that you are using a computer at work. If you are using a computer at work, you can ask the company system operator to open the following port.
*The port number is 7447, 7002.
*If you are using your personal computer, choose “Exceptions” tap at Setup-Control Panel-Windows Firewalls and check Upcheck.exe as an exceptional item.
5. Incorrect password digit
The maximum password digit is 8.