1s-bitrix - why do letters end up in spam?

Question

1C-Bitrix

I made an email newsletter. I test it by sending it to my mail, but the letter always ends up in spam .
The mail itself, on behalf of which I send the newsletter , is completely trained as it should - spf, dmarc. dkim. ..

I think that Bitrix somehow cleverly sends letters, as a result of which they end up in spam.
If you send a letter manually from my mail, then everything is OK, but if through bitrex, then spam.
How to fix it? How to set up mail on 1s-bitrex? smtp is not there, as far as I know.