Hi @Dejan Kocic ,
I realize this is an old post and I'm betting this has since been resolved. However I thought I would answer in case others happen upon this post.
Generally what I start with is looking at the email logs under project settings then email requests and click on the link for view logs. You should see a failure message that may give a clue as to what's going on. A good example of that is the email is coming from a user that does not have access to the project i.e. they have not been defined as a customer.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.