Events Manager not sending mails

I am having difficulties with sending automated mails from Events Manager, all other functions like Newsletter and automated mails from WP are working.

Everything is set over SMTP, and even if I press test button, it says test successful, but when I try to reserve a spot on the event, it goes through, but it displays the message that something went wrong, and that mail is not send.

Same happens when I try to delete or cancel a ticket on a event from admin, it says for example: Booking rejected. ERROR : Email Not Sent.

SMTP details are correct, as newsletter goes through, and Events Manager test mail works.

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