Hello.
I have tried to set up a notification from gmail, no success, moreover I see no errors from setup window I mean, I can left blank the field "email address" or other field then push TEST and I see no red errors in bottom of this window which I could see on other screenshots. Same things with telegram test, so I even don`t know or test button works at all or doesnt work notification itself.
P.S. Tested it under real conditions, it really doesnt work.
Version 6.39.2

kvach,

As you use Dude v6, you can find some information about failed email notification inside Logs of RouterOS.
Screen with working example for Gmail you can find in this forum post: Email Notifications - General Tab Missing!!!

Thank you!

kvach,

This post may be helpful: Dude v6 - Email notification through Gmail

Doesnt work anyway. Or there any limitations of free license?

kvach,

Do you use Dude on CHR?

Email notification in Dude v6 working - this was verified.

You should investigate why it doesn't work in your case.
For example, you can use https://github.com/changemakerstudios/papercut as an Email server.