Try:
Code:
player = players[i]
new steam_id[34], dumb[130]
get_user_authid(id, steam_id, 33)
format(dumb, 129, "amx_ban %d %s Reason: You suck.", czas, steam_id)
log_to_file("logs.log", "%s", dumb)
server_cmd("%s", dumb)
Using Amxbans 5.0, you don't need quotation marks around the reason.
So take a look into your logfile, if ban command is written right way.