client freezes at character selection

[Nuer]

Hi everybody,

I'm an old player, back to RO after some years.
I started palyng again around a couple of weeks ago, everything was working.

since a couple of days ago I cannot enter the game, because the client freezes as soon as I press "Play" button at the character selection screen.
the sound goes on playing the theme, but the screen is stuck, except for some twitches of the character.

I tried to force safe mode, it looks like it solved the issue, but in the very next screen the loading bar stops @15% and after a couple of minutes an error message appears: "you have been disconnected by the server, please try to relog" (or something similar).
OFC, trying to relog gives the same result.

I tried to change some video settings (fullscreen on/off, different resolutions) but nothing changed

my distro is Ubuntu Studio 16.04 (xfce)
I did not install/uninstall/change anything before the game stopped working.

any possible solution?

tnx a lot