I'm using v3.10 and when i was trying to set the e-mail parameters i had a strange problem. I was setting the e-mail from parameter and i have given the email address as email.domain.com instead of email@example.com mistakenly. My routeros stopped and i got a disconnect message from winbox.
Then i can reach it via ssh over an internal ip but i can not reach it over winbox again. I tried several configuration changes at the mean time like changing the pref-source of a route and it does not operate. I decided to reboot the router and it becomes available but on the log it says "system error critical and rebooted because of kernel failure".
Just to let the mikrotik guys aware about it.