I'm trying to upgrade test cassandra cluster from 3.11.17 to 4.1.5, I wanted to do in rolling fashion so upgrade was done on the first node but the node is not is not starting up with the below error. Can you please let me know what is the issue here

INFO  [Messaging-EventLoop-3-21] 2024-07-30 04:46:26,203 NoSpamLogger.java:105 - /host1:7000->/host2:7000-URGENT_MESSAGES-[no-channel] failed to connect
io.netty.channel.AbstractChannel$AnnotatedConnectException: finishConnect(..) failed: Connection refused: /host2:7000
Caused by: java.net.ConnectException: finishConnect(..) failed: Connection refused
    at io.netty.channel.unix.Errors.throwConnectException(Errors.java:124)
    at io.netty.channel.unix.Socket.finishConnect(Socket.java:251)
    at io.netty.channel.epoll.AbstractEpollChannel$AbstractEpollUnsafe.doFinishConnect(AbstractEpollChannel.java:673)
    at io.netty.channel.epoll.AbstractEpollChannel$AbstractEpollUnsafe.finishConnect(AbstractEpollChannel.java:650)
    at io.netty.channel.epoll.AbstractEpollChannel$AbstractEpollUnsafe.epollOutReady(AbstractEpollChannel.java:530)
    at io.netty.channel.epoll.EpollEventLoop.processReady(EpollEventLoop.java:470)
    at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:378)
    at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
    at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
    at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
    at java.lang.Thread.run(Thread.java:750)

host1 - Is the IP address of the node where upgrade was done host2 - is the existing node in cluster with previous version

Thanks