I recently installed flask application on nginx Ubuntu Linux server, and when I run "flask run -h 0.0.0.0 -p 1234", it is working in localhost:1234/list if I call API but when I try to call from postman or external It is not at all working "enterned command: "flask run -h 11.222.11.222 -p 1234" and throws an error: "OSError: [Errno 99] Cannot assign requested address".

I have also allowed port number i.e. 1234, still, it is not working. Can anyone help me out with how to assign localhost to IP address or domain name so that flask API can work externally.

I'm new to this server setup and deployment.

Thanks in advance.