Jupyter Notebook远程启动时出现Unable to

Unable to round-trip http request to upstream: dial tcpxxx.xxx.xx.xx:xxxx: connect: connection refused
出现这种报错信息一般是因为防火墙问题，需要为端口开启防火墙,并重启:

firewall-cmd  --zone=public --add-port=你的端口/tcp --permanent #将端口加入防火墙
systemctl restart firewalld.service #重启防火墙