What factors affect mail filters?

Question

gmail

I have several online stores and we send monthly letters to our customers about new products, special offers and innovations. Last year, I began to notice that the number of clicks from mailing lists has noticeably decreased.
I did a test: I sent it to my boxes and a partner. The result is strange - I have it on gmail, my partner does not. Ie not at all (spam is empty). Mail.ru is also empty.

I can't figure out why this is happening. Maybe someone came across?
I send the newsletter via sendgrid.com.

Answer 1

In this case, nothing can be answered unequivocally, too little information.
1) gmail will never refuse to accept mail, in the worst case it will mark the letter as Spam.
2) Mail.ru, on the contrary, if they consider the server through which you send mail as spam, then the letter will not be accepted, which should leave a record in your server log. This information should be provided to you by sendgrid.com. Then you can contact the mail.ru support service, after 2-3 days of correspondence I usually managed to get added to the "white list
" , check forward/reverse zones, etc.
All of the above usually helps. If you have any questions please contact.

Answer 2

check your mailings against blacklists, etc.

Answer 3

There can be a lot of factors, and if an oboinik does not come from the service, then find out why it’s unlikely to work out. But given that a third-party service is used, there is nothing surprising. Somewhere, it means that the clients of the service were spammed, and they were banned. If you have completely legitimate mailings, all the more beneficial, then you need to at least think about your mailing service, and at most, get your own mail server.

Answer 4

Personally, I would start by asking sendgrid.com for the full mailing log. In theory, they should provide it. I would look at it and highlight the responses of the mail servers where the letters did not reach. And further on circumstances.