Yes.. I did have a check on that before going for the upgrade, never really thought that there will be an issue with Provisioning.Yes, but there is another problem. If you check the supported devices page for the SPA, and specifically in the Limitations section, you will see that this phone is listed as not supporting any kind of remote provisioning...
If it is the drop-down menu for "provisioning method" under IP Phone, yes. I don't have the options for STUN or SBC.I though at some point that you mentioned that you were provisioning the phone Locally to the 3CX Server. Anyhow, you shouldn't even be getting the options for Remote STUN or SBC in the drop-down.
Cisco SPA phones don't "like" HTTPS provision, and 3CX >V15 doesn't "like" HTTP requests from public IPs that aren't HTTPS, that is the conflict.
So, taking a step back here, the questions is, who is the phone trying to connect to the 3CX Server:
- Over the internet (STUN or SBC)?
- On the same physical LAN as the 3CX Server?
- Over a site-to-site VPN that connects the remote site where the phone is to the 3CX Server?
Founded in 2005, when VoIP was an emerging technology, 3CX has gone on to establish itself as a global leader in business communications.