"Internal Execption: java.io.IOException: an existing connection was forcibly closed by the remote host" error message

Heres a problem, Yesterday night i've been invited to an aternos server, which is 1.16.3, I joined the server but for 10 seconds (or more) i get disconnected and have that error message. I did this multiple times like 10 or 15 times and still doesnt work. So i complained about this message that i'm not compatible with 1.16.3 so the server owner changed the server version and it did work, only for a day. When i came back to play on the server, I got the same thing and connecting 12 or more now.