VPN Client disconnects every hour

[Teddy_Marchandi]

All my VPN client disconnect after one hour live connection. Issue happens on Mac OS or Windows OS.
Gateway is on 81.10  and most VPN clients are on 86.50
From smart console I see a user has signed off messgae after one hour being connected.
From client logs I see "Failed to renew encryption keys"

Already applied fix mentioned below, but still having same issue

TAC (SR 6-0001915434).

change the parameter on file $FWDIR/boot/modules/fwkern.conf:

natt_probe_do_in_kernel=0

Thanks for your help