I have a program which sends email to customers using Yandex SMTP server. But I frequently get:
554 5.7.1 [2] Message rejected under suspicion of SPAM; https://ya.cc/1IrBc 1593708139-nzbnbCCRfk-gIZ4AKCg
I have set following headers on each email request:
headers["Content-Type"] = "text/html; charset=UTF-8"
headers["Date"] = time.Now().Format("Mon, 02 Jan 2006 15:04:05 MST")
How can I prevent this error? Is there any settings or header which I can set for that?