P315 DPMA issues

Good morning, we have purchased 200 Sangoma P315 phones to connect to our FreePBX Distro server. Even though DPMA seems to work, we still can’t register the phones.
The FreePBX server is configured to answer phones on a dedicated VLAN from the eth1 interface. We have activated Sangoma One Touch Provisioning to provide the address of the server’s eth1 interface at boot. However, the process is not successful, as the phone sends packets on port 443 to the server’s public address (eth0 interface). The DPMA and Endpoint Manager configuration seems correct, following the documentation. We don’t want to have to resort again to provisioning based on TFTP and XML configuration files that we provided with other brand phones.
Thank you

Looks like something wrong with the EPM configuration. Can you check why the phone is sending packets to port 443? It should be hitting the SIP port (5060) of the PBX when using DPMA.

I don’t know why! DPMA is correctly configured (mDNS, etc). Phones get configurations from correct internal template, but then sip server answers somewhere with its public IP and communications between host and phone go over two different routes, I think. Rebooting phone don’t resolve impasse… I don’t know where is the problem!