Cannot login/create/restore realm: io.netty.channel.abstractchannel$annotatedconnectexception

I cannot join my friend's(IGN: tamagoboro) realm server because of error message, and it has been 2 days.

We've got error message everytime : "io.netty.channel.abstractchannel$annotatedconnectexception" .
We've tried to reset my internet connection to join server, but so far, nothing works.
My friend also tried to remake world/backup/restore realm, but nothing works.

Please check the message and if you need more information. please let me know to solve problems
Thank you.