You are used to AWS Security Groups. You created a firewall rule in GCP. You cannot seem to reach the GCP server. What is wrong?
Does the GCP firewall rule use the same shorthand notation like this?
Inbound rules in AWS Security Groups use the /32 to allow an IP address to connect to an EC-2 instance or service. For GCP, this /32 will not work. Use /24 or something along those lines.
You may want to see this "How Do You Get a GCP Server to Present a Website on the Internet?" for details.