Had the same issue with hack protection. I'm using windows 10 and i couldn't join. There's a fix for it tho.
If you look inside the Exteam-MuOnline97 Client file, you'll see a file called main.exe and main.exe.bak . Rename main.exe to something else for example main.exe.blabla and then rename main.exe.bak to main.exe . Then you'll be able to join without issues.
https://i.gyazo.com/7a2d5e2bf63b749c...30d7f4f405.png
there are a few issues with the server tho. It seems that finding rare items or at least good items is very difficult. i'm 10 RR and still using shop items. Hunted several golden kunduns and half of them never dropped +5 box...
There are also issues with the website such as rankings aren't working and we can't reset our character through website. Reset is at 350 and max level is 350 but website says that we lack 50 more level which is impossible to reach due to 350 being max level. Good thing that /reset command works..





