I am hosting a vanilla server with friends and one of them cant connect

I hosted a vanilla server to play with friends, and after playing a few hours, one of my friends wanted to join the server, but he gets the following error:

"io.netty.channel.abstractchannel$annotatedconnectexception connection refused no further information"

 

Any other server works for him. He already:

• Turned off and on his internet
• Turned off his Windows Defender (also allowed all Java's things in public and private)
• Uninstalled uTorrent
• Restarted his computer
• Checked that the ip and port was right without any spaces
• Tried to connect by Direct Connect and Add Server
• Closed any program besides Minecraft.
• Re-installed Java

He is the only one that gets this error.

****Affected version: is 1.14.4. But it doesnt let me select that version