Проверка blacklist: https://mxtoolbox.com/blacklists.aspx Тест письма: https://www.mail-tester.com Постмастеры: - https://postmaster.google.com (Gmail) - https://postmaster.live.com/snds (Outlook, Hotmail, IP only) - https://developer.verizonmedia.com/mail/ (Yahoo/Verizon) - https://postmaster.mail.ru (CIS) Рейтинг вашего IP для Yahoo/Hotmail - https://senderscore.org