You can also expliciitly whitelist each of the server hosts.
In addition, in FreePBX “context=default” should be throwing an error. Try something like “…=from-trunk”.
The DTMF mode selection may not work reliably as well. If it works for you, good, but if you have trouble with digits not working in IVRs or in Voicemail, you may need to narrow your DTMF Mode selection down a little bit.
Only use “type=friend” if the address you specified can receive calls from your PBX as well as deliver calls to your PBX.