https://github.com/kubernetes/ingress-nginx/tree/main/docs/examples/grpc
In the above link under Prerequisites - 2nd point, it is mentioned to have a domain name configured to Ingress controller.
How to create or get a domain name in AKS? I have a grpc application, trying to implement the same steps.
You have two Options, for both you need an own a domain Name (you can buy it at namecheap.com or godaddy.com).
First option: Switch the domain DNS resolution to Azure..
Second option: Create the AKS and add it as CNAME (AKS public FQDN, i would prefer this over using the IP) to the DNS records of your domain.