When some kind of traffic (mostly VoIP) take place to AP the MT routers reboots 
One after one within ~1minute. Watchdog is set to default values:
reboot-on-failure: yes
watch-address: none
watchdog-timer: yes
Versions of MTs are 2.9.2 and 2.9.6 and connected via nstreme
2.9.6 works as nstreme AP
What the matter can be? Which way to dig? Hardware or software?
Thank you.
check the files, maybe there is a autosupout.rif file generated after reboot. If yes, then please send it to support@mikrotik.com
Also you can upgrade to the latest version of the RouterOS and put the Wireless-test package and check if the router still reboots.
oles,
How much traffic are you having? Are you sure they’re rebooting due to type of traffic and not due to amount?
What hardware are you using?
Reboots stoped when we disabled service-ports in /ip firewall
try enabling them one by one.