Received response: "Forbidden"

Had this same issue about a week ago with a UK number. All domestic and other international calls go through just fine. Here’s a snippet from the debug log:

[2016-12-06 12:19:17] VERBOSE[10634][C-000001da] app_dial.c: Called SIP/flowroute/0116788282425
[2016-12-06 12:19:17] VERBOSE[10636][C-000001da] app_mixmonitor.c: Begin MixMonitor Recording SIP/403-0000005a
[2016-12-06 12:19:17] DEBUG[10636][C-000001da] audiohook.c: Read factory 0x7f7d48298b68 and write factory 0x7f7d482995a8 both fail to provide 160 samples
[2016-12-06 12:19:17] DEBUG[20214][C-000001da] chan_sip.c: (Provisional) Stopping retransmission (but retaining packet) on '[email protected]' Request 102: Found
[2016-12-06 12:19:17] DEBUG[20214][C-000001da] chan_sip.c: Acked pending invite 102
[2016-12-06 12:19:17] DEBUG[20214][C-000001da] chan_sip.c: Stopping retransmission on '[email protected]' of Request 102: Match Found
[2016-12-06 12:19:17] DEBUG[20214][C-000001da] chan_sip.c: ** Our capability: (alaw|g729|ulaw|g722|g726) Video flag: False Text flag: False
[2016-12-06 12:19:17] DEBUG[20214][C-000001da] chan_sip.c: ** Our prefcodec: (alaw)
[2016-12-06 12:19:17] DEBUG[20214][C-000001da] chan_sip.c: (Provisional) Stopping retransmission (but retaining packet) on '[email protected]' Request 103: Found
[2016-12-06 12:19:18] DEBUG[20214][C-000001da] chan_sip.c: Acked pending invite 103
[2016-12-06 12:19:18] DEBUG[20214][C-000001da] chan_sip.c: Stopping retransmission on '[email protected]' of Request 103: Match Found
[2016-12-06 12:19:18] WARNING[20214][C-000001da] chan_sip.c: Received response: "Forbidden" from '"xxxxxxxxxxxx" <sip:[email protected]>;tag=as5e486071'
[2016-12-06 12:19:18] DEBUG[10634][C-000001da] channel.c: Hanging up channel 'SIP/flowroute-0000005b'
[2016-12-06 12:19:18] DEBUG[10634][C-000001da] chan_sip.c: Hangup call SIP/flowroute-0000005b, SIP callid [email protected]
[2016-12-06 12:19:18] DEBUG[10634][C-000001da] res_rtp_asterisk.c: Setting RTCP address on RTP instance '0x7f7d488edf78'
[2016-12-06 12:19:18] VERBOSE[10634][C-000001da] app_dial.c: Everyone is busy/congested at this time (1:0/0/1)

I’ve emailed Flowroute with the number being dialed to see if they’d reject it for some reason. Anything else I can try in the meantime?

Thanks.

I don’t see how this relates to FreePBX. Seems to be ITSP specific issue.
Instead of looking into regular Asterisk log check your sip debug. Some ITSP are providing additional information like real disconnect reason in the body of the error message.

in my experience this is usually a bad/disconnected number.

Turns out the destination country had a calling rate above our threshold. Easy fix.