VirtualService is exported to only current namespace by setting exportTo set to "." not working for gateway object created in the same namespace

I am using istio 1.7.6 version. I have exported virtual service only to the current namespace by configuring exportTo: “.” . The gateway configured in this virtual service is also present in the same namespace. But still the service is not reachable. However, when I set exportTo as “*”, it becomes reachable.
Can you please suggest what could be the possible reasons for it to not work and how to resolve it?

Please have a look into this.