Hello ALL!
In an organization there are two mail domains.
The first "office.com" second "office" Correspondingly mailbox names first server "mail1@office.com", "mail2@office.com". Second server "mail1@office", "mail2@office".
Mail runs between them. But after RoundCube, box "mail1@office.com" no mail is sent to the boxes "mail1@office". Via e-mail client MS poisoned mail.
In this pop up error "Invalid e-mail address: "
Which way to dig?