@JuergenAuer I'm pretty sure @alliwantistest didn't start this thread because of problems of getting a certificate for his hostname. He/she literally says he/she's trying to "host an API service" and has trouble "sending requests to the server", assuming "the server" is his/hers own server.
@alliwantistest Could you please elaborate on the set up of "the server" hosting your API service? What does it actually do? What webserver is your API running? From where did you connect to your service? With what client are you trying to connect to your service?
Who's blocking what? You're trying to connect to your own service, correct? Then you're blocking yourself?