OVH sur Asterisk: trunk Reachable - Unreachable, normal ou pas?

Bonjour,

Je viens de prendre un forfait à 0,99€ et un numéro belge.
Je l'ai configuré sur Asterisk (FreePBX) pour l'utiliser avec les 3 téléphones qui sont dans ma maison + portier SIP. Néanmoins je constate dans les logs que le trunk est défini comme Unreachable régulièrement (une dizaine de fois par heure) et redevient Reachable qq secondes après.

Voici une partie des logs:
[2019-09-23 14:57:57] NOTICE[495] chan_sip.c: Peer 'OVH' is now Reachable. (17ms / 300ms)
[2019-09-23 14:59:58] NOTICE[495] chan_sip.c: Peer 'OVH' is now UNREACHABLE! Last qualify: 18
[2019-09-23 15:00:08] NOTICE[495] chan_sip.c: Peer 'OVH' is now Reachable. (19ms / 300ms)
[2019-09-23 15:01:09] NOTICE[495] chan_sip.c: Peer 'OVH' is now UNREACHABLE! Last qualify: 19
[2019-09-23 15:01:40] NOTICE[495] chan_sip.c: Peer 'OVH' is now Reachable. (17ms / 300ms)
[2019-09-23 15:08:41] NOTICE[495] chan_sip.c: Peer 'OVH' is now UNREACHABLE! Last qualify: 19
[2019-09-23 15:09:01] NOTICE[495] chan_sip.c: Peer 'OVH' is now Reachable. (18ms / 300ms)
[2019-09-23 15:13:02] NOTICE[495] chan_sip.c: Peer 'OVH' is now UNREACHABLE! Last qualify: 16
[2019-09-23 15:13:22] NOTICE[495] chan_sip.c: Peer 'OVH' is now Reachable. (18ms / 300ms)
[2019-09-23 15:16:23] NOTICE[495] chan_sip.c: Peer 'OVH' is now UNREACHABLE! Last qualify: 16
[2019-09-23 15:16:44] NOTICE[495] chan_sip.c: Peer 'OVH' is now Reachable. (19ms / 300ms)
[2019-09-23 15:26:44] NOTICE[495] chan_sip.c: Peer 'OVH' is now UNREACHABLE! Last qualify: 18
[2019-09-23 15:26:55] NOTICE[495] chan_sip.c: Peer 'OVH' is now Reachable. (17ms / 300ms)
[2019-09-23 15:34:55] NOTICE[495] chan_sip.c: Peer 'OVH' is now UNREACHABLE! Last qualify: 19
[2019-09-23 15:35:05] NOTICE[495] chan_sip.c: Peer 'OVH' is now Reachable. (17ms / 300ms)
[2019-09-23 15:42:06] NOTICE[495] chan_sip.c: Peer 'OVH' is now UNREACHABLE! Last qualify: 18
[2019-09-23 15:42:16] NOTICE[495] chan_sip.c: Peer 'OVH' is now Reachable. (18ms / 300ms)
[2019-09-23 15:49:17] NOTICE[495] chan_sip.c: Peer 'OVH' is now UNREACHABLE! Last qualify: 22
[2019-09-23 15:49:27] NOTICE[495] chan_sip.c: Peer 'OVH' is now Reachable. (18ms / 300ms)
[2019-09-23 15:51:27] NOTICE[495] chan_sip.c: Peer 'OVH' is now UNREACHABLE! Last qualify: 17
[2019-09-23 15:51:37] NOTICE[495] chan_sip.c: Peer 'OVH' is now Reachable. (18ms / 300ms)
[2019-09-23 15:54:38] NOTICE[495] chan_sip.c: Peer 'OVH' is now UNREACHABLE! Last qualify: 19
[2019-09-23 15:54:48] NOTICE[495] chan_sip.c: Peer 'OVH' is now Reachable. (18ms / 300ms)
[2019-09-23 15:55:49] NOTICE[495] chan_sip.c: Peer 'OVH' is now UNREACHABLE! Last qualify: 18
[2019-09-23 15:56:09] NOTICE[495] chan_sip.c: Peer 'OVH' is now Reachable. (18ms / 300ms)
[2019-09-23 15:57:10] NOTICE[495] chan_sip.c: Peer 'OVH' is now UNREACHABLE! Last qualify: 18
[2019-09-23 15:57:20] NOTICE[495] chan_sip.c: Peer 'OVH' is now Reachable. (18ms / 300ms)

Aurais-je omis un paramètre ?

Voici la config du trunk

host=sip5.ovh.be
username=XXXXXXXXX
secret=XXXXXXXXX
type=peer
qualify=300
insecure=very
canreinvite=no
fromuser=XXXXXXXXX

Aussi, j'utilise FreePBX dans un docker sur un NAS Synology, pourrait-il que ce soit lié?

Merci pour votre aide! :)