Is your anti-virus program or firewall settings blocking Dragon Nest SEA from accessing the Internet? Add Dragon Nest SEA client files (dnlauncher.exe and dragonnest.exe) onto your firewall exceptions list.
Ensure you have administrative rights on your personal computer. Launch dnlauncher.exe as a Windows Administrator (right click on dnlauncher.exe and click on "Run as Administrator").
Use a wired Internet connection to connect to Dragon Nest SEA, as wireless connections tend to be unstable due to varied reception coverage.
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