How to make sure that letters from a corporate mailbox do not fall into spam?

Question

Mail for domain

The company has a domain, hosting - masterhost. The domain has corporate mail. The problem is that in the last week the letters that we send to clients on mail.ru mailboxes began to fall into spam.
Nobody sends spam, there are no mailings. General business correspondence.
How to increase mail.ru trust? Can transfer the domain to "corporate mail" yandex, let them be hosted on yandex servers.

Answer 1

Try PDD.Yandex , but it's not certain that it will help, because your domain is most likely blacklisted.
Also, register on postmaster.mail.ru so that you have the opportunity to see specific problematic letters and understand the reasons. With this data, you can already write to Mail.ru support if necessary. True, you need to be patient, they do not answer very quickly + the first couple of answers will be the usual "unsubscribes".