Which SMTP provider provides the best deliverability?

Question

Email

Good afternoon
Our corporate mail is located on our servers. When sending from office IPs, sometimes mail goes to spam on Gmail (All settings are made by mail-tester.com does not show any errors).
We want to use a service from one of the operators of smtp services such as mandrill, sendgrid, mailgun.com
Advise which service will provide maximum deliverability? Thanks

Answer 1

you want to run away from the problem. and if you configure spf / dkim, then the probability of not getting into "spam" will greatly increase