Learn more about this change here.
For help regarding Aternos, we recommend you to visit our support center.
Are you using the same version of the modpack that is on the server?
i took the version on twitch rad lite 1.2.
________________
Please check again now
i can play on the server now, and i see a little error in the log. But its not myabe a problem for play :s
thank you.
i found this on the historic:
but nowwhere i cant this "craftstudio API", why the server claim it ???
i tried to install on my PC 2 version of craftstudio and that does not solve the problem...
I go on Version > Modpack > install RAD pack(LITE), launch minecraft but when i join the game i have : craftstudio API: Requires version 1.0.0 but mod is not found on client.
How i that possible ? when i go on curse RAD Lite it doesent use craftstudio... i dont understand !? aternos install a mod that is not in the mopack !?
And u cant check what mod is installed on the server or i dont find where 
(sry im french)
