It seems the acweb started the assettocorsa server successfully, but it also changed working directory into assetto's directory rather than acwebs... so the server complained cannot find those configurations: configs/4/server_cfg.ini NOT FOUND
and after I set the symbolic link '/home/steam/assetto/configs' -> '/root/v1.4.2_linux_64bit/configs/' it then starts fine.
It seems the acweb started the assettocorsa server successfully, but it also changed working directory into assetto's directory rather than acwebs... so the server complained cannot find those configurations:
configs/4/server_cfg.ini NOT FOUND
and after I set the symbolic link
'/home/steam/assetto/configs' -> '/root/v1.4.2_linux_64bit/configs/'
it then starts fine.