The phone is auto provisioned over https / ssl with option 66 set up on the router. It is configured to use the SSL port https://user:pass@fqdn:1443, and it provisioned automatically, so I assume it used that.
The GUI is also accessible over SSL and is working correctly, since the browser accepts the ssl certificate.
I confirmed that the XML-API phone apps are working on S-series phones and the template has PhoneApp Protocol set to HTTPS.
The Digium phones use the DPMA apps through EDM. Digium Phones Config module is not installed.
I just can’t figure out what the issue is.
Do you have any troubleshooting procedures I can go through to confirm that SSL is configured correctly for this phone?