How to check why emails do not come.

Hi, i have CyberPanel

Sender logs
2019-11-28 10:25:22 1iaG38-0001mZ-Ol <= 1@1.com H=(a.b.pl) [::1]:53482 P=esmtpa A=dovecot_login:1@1.com S=599 id=308234bc029e83a833e19a783bb7b6af@1.com T=“kolejny test maila” for 2@2.pl
2019-11-28 10:25:23 1iaG38-0001mZ-Ol => 2 2@2.pl R=virtual_user T=dovecot_virtual_delivery C=“250 2.0.0 2@2.pl oHRDNIKS311jYAAACGA+Wg Saved”
2019-11-28 10:25:23 1iaG38-0001mZ-Ol Completed

I don’t have an email from this sender. E-mails come from other senders. Eg from Gmail.
But I don’t know how many do not come and who is filtered.

systemctl status dovecot = active (running)

i cant see any line with 1@1.com in /var/log/maillog :frowning: