I need help with a problem. In my context I need to put a Middleware between Shopify and another cloud software. I must recieve a json from Shopify but they needs a valid https URL. I have a Centos VPS running my app but when I generate a certificate, I receive an untrusted message and works in postman with an advice but obviously doesn’t works with Shopify. How could I proceed with this? Because my server only have an IP not a domain, so I can’t buy a certificate.
I tried to create an certificate, but I didn’t get a good result with that
The short answer is: you cannot have an SSL certificate that is not bound to a domain.
So, instead of buying an HTTPS certificate, you should go first buying a domain name and bind this to your IP.
Then you can create an SSL for free using Let's Encrypt.
Of course, once you have bought your domain, you have to configure nginx or Apache on your server.