A2billing "no card number has been entered" error

Custom destination configured from FreePBX/Asterisk to A2billing server and receiving “no card number has been entered" error. No DTMF tones seem to be detected as well.

The below settings are configured on the inbound SIP trunk to the PSTN provider:

type=peer
host=10.102.102.15
dtmfmode=RFC2833
rfc2833compensate=yes
relaxdtmf=yes
canreinvite=yes
faxdetect=no
nat=yes
externip=xxx.xxx.xxx.xxx
externrefresh=5
localnet=192.168.0.0/255.255.0.0

Any ideas?

Asterisk 3.0.0
A2Billing Version 3

accountcode=???

A2Billing needs to associate the call with an account.