To directly answer your question I'm not sure if the out of the box email action has its own log file - I don't see one in my deployment so you can probably just look in the Server.0.0.log to see if there was any issue with the incident or action firing. I expect anything to be contained there.
First though I would want to verify that the email action in your incident doesn't have the 'smart alerting' checkbox selected, and also want to make sure you are seeing emails for other incidents. Make sure you can send emails at all - there's an option to send a verification email in the server settings -> services -> email tab.
Thanks for answer.
Didn't find any incident info in server log, will searching further.
I checked email sending - it works.
Could you tell me why i should to uncheck 'smart alerting' checkbox ?
Smart alerting has a place - but it is probably not the behavior your want and the last I checked for the standard email action it gets enabled by default.
What it does is that after the first occurrence of an incident it will deliver the first email but will suppress emails for any later incidents that occur until a user logs into the client, visits an incidents dashlet and right-click -> confirms the incident. It allows you to suppress emails for an incident that is already being worked on but often this is the cause of not receiving an alert even though an incident is detected.