Multiple domain email
Hello good afternoon
I moved all my websites from a shared host to a DO's droplet. I installed VestaCP to manage everything. For about a week emails worked fine... But yesterday starts an error... All emails sent, is being delivered as spam (Google) or not being delivered (domains hosted on another hosting)... If I send a email to another domain that is on the same droplet i receive the message...
The result of the comand sudo tail /var/log/exim4/mainlog returns this
2018-04-06 16:08:42 1f4Tuq-0001uR-GN H=mx-vip-02-farm74.uni5.net 1.2.34]: SMTP error from remote mail server after RCPT TO:firstname.lastname@example.org: 450 4.7.25 Client host rejected: cannot find your hostname, [18.104.22.168]
Digital Ocean droplet: name -> maindomain.com.br
DigitalOceans Domains: All domains hosted on the droplet
Digital Ocean DNS: All domains have 3 ns entries, and one more A @ pointing to droplet IP
VestaCP: using basic VESTACP domain's DNS
Anyone can help me?