Hi Wang, Zheng,
It looks like you can't access to Azure ML workspace after add your public IP on the network settings, In that case I suggest you to check you IP public:
On terminal: curl ifconfig.me
Sometimes the home internet providers is outbound the traffic from different public Ips dinamically. You can try adding your public ip but with a broad network range: 80.x.x.x/24 . Take in consideration that this only for testing/development purpose not for production environments.
References:
If the information helped address your question, please Accept the answer.
Luis