Does wp_mail() go to spam via smtp?

Question

C++ / C#

Set up smtp. On @mail and @gmail letters get into the inbox, and on yandex they go to spam. With what it can be connected?

Answer 1

var filtered = content.Where(x=>(decimal) x["date"] >= 100 &&(decimal) x["a"] < (decimal) x["b"] );

Answer 2

Smtp own or smart host relay?
If the first - you need correct records in DNS - MX, SPF, DKIM, optional DMARC. Otherwise, they will go to spam.