Here looks to be the reason:
018-06-08 10:49:14.540960 [ERR] sofia_reg.c:2616 Cannot locate any authentication credentials to complete an authentication request for realm '"jdevo.com"'
2018-06-08 10:49:14.540960 [NOTICE] sofia_reg.c:2639 Hangup sofia/external/
07946822853@jdevo.com [CS_EXECUTE] [MANDATORY_IE_MISSING]
So my guess is there is some sort of reinvite caused by the session timers being enabled:
INVITE sip:07946822853@62.7.201.169:5060 SIP/2.0
Via: SIP/2.0/UDP 52.51.48.253:5080;rport;branch=z9hG4bKjjar6m2B2392B
Max-Forwards: 70
From: "01282 678401" <sip:
441282678401@jdevo.com;user=phone>;tag=U4S01aD2r050j
To: "+447946822853" <sip:
07946822853@jdevo.com>;tag=3737439697-471166132
Call-ID:
10294995-3737439697-809996478@sbc-uk-bs09b.ipcomms.bt.net
CSeq: 123889613 INVITE
Contact: <sip:441282678401@52.51.48.253:5080;transport=udp>
User-Agent: FreeSWITCH
Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, INFO, UPDATE, REGISTER, REFER, NOTIFY
Supported: timer, path, replaces
Session-Expires: 900;refresher=uac <---------------------------------------------
Min-SE: 120 <----------------------------------------------------------------------------
Content-Type: application/sdp
Content-Disposition: session
Content-Length: 220
I would check the gateway config though I do not understand why the call would even initiate.
Its implying there is no username/password in the gateway.