Do you have an all-in-one setup or a distributed setup?
If its a distributed setup, you will see some logs in the gateway instance whenever an API is deployed in the Gateway. If you do not see such logs that means that API deploy notification is not sent to the gateway properly from the control plane. This could happen if the event_listening_endpoints available under eventhub config isnot properly defined in the deployment.toml of the gateway.
[apim.event_hub]
enable = true
username = "$ref{super_admin.username}"
password = "$ref{super_admin.password}"
service_url = "https://[control-plane-host]:${mgt.transport.https.port}/services/"
event_listening_endpoints = ["tcp://control-plane-host:5672"]
Please note that the above is a sample configuration taken from the WSO2 docs. But if you have a distributed setup, you need to have this configuration in the gateway to connect the gateway to the control plane to receive notifications. Please refer the official documentation [1] for more info on this.
This issue should not be ideally there if you have an all-in-one setup. But you can still check the hostnames and verify whether something is wrong there.
Another thing you can do is restarting the gateway to see whether the issue is resolved. If that is the case, you can narrow it down as an issue with the notification sending between the gateway and the control plane.