The public IP it tries to resolve to is not the one it needs to resolve to. Our public pbx ip is not listed in that message. Also curious about the double slash after domain.
Right now, that address seems to resolve to 40.130.71.46. Is that the correct IP address for your public IP address? Did you start using a CDN between when you previously obtained a certificate and now?
What software and command are you trying to use to obtain the certificate?
Well, I can’t connect to any HTTP service on 40.130.71.46 at all (with a browser or curl). I don’t know anything about FreePBX, so I don’t know if it’s supposed to run a web server for you or if you’re supposed to run your own web server or what, but I also can’t connect there. Somehow, the certificate authority will need to connect to a web server there in order to prove your control over the domain name.