If API is chosen in Portal API and you choose SUBMIT to check if you get a response, nothing shows up. There are no error messages either.
All supported versions of the API Portal
In the portal machine, open the /etc/hosts file. Create an entry with the portal IP and <tenant_name>.<domain-name.com> and <tenant_name>-ssg.<domain-name.com>
See the following section in the documentation to update the hosts file
Edit Hosts File for Local Access
Example: If tenantABC is your tenant then your entry would look like this in /etc/hosts
126.96.36.199 tenantABC-ssg.domain.com tenantABC.domain.com