From my experience it is not the NTP server but the SNTP client
causing the reboots. Disabling the SNTP client solved it for me
so far. (>20 days).

There are reboot issues with the non wifi version as well.
See viewtopic.php?f=2&t=158939

Greetings

Mikrotik support first wanted me to try the latest RouterOS beta and then told me to open a RMA warranty repair with my distributor. They did not say if this is software or hardware related. Looking at the other RB4011 cases on this forum https://forum.mikrotik.com/viewtopic.php?f=2&t=149062 I t...

Same here with a RB4011iGS+RM. Tried with different RouterOS versions all the way to the latest beta. Changed power supplies and everything is running of a UPS anyway. Still reboots every few days. Best advice is to open a support case. Send my RB4001 back for RMA warranty repair and waiting for the...