I have two Email Service providers (SMTPs) for my multiple emails of same domain. and i configured multiple MX record on my domain records for both SMTPs. one is hostpoint SMTP for email address office@mydomain.com second is protonmail for email address xyz@protonmail.com and i also have alias of my other domain emails on protonmail like ceo@mydomain.com,admin@mydomain.com & office@mydomain.com both accounts (office@mydomain.com & xyz@protonmail.com) are configured using IMAP settings Also i defined a rule for incoming email of office@mydomain.com to copy in xyz@protonmail.com account's INBOX Now when i reply a copied email in account xyz@protonmail.com it add xyz@protonmail.com and office@mydomain.com in TO address field by default. So, there is an unnecessary office@mydomain.com address in TO field (which is original account address or you can say copy from account) i have not set any rule for it or my to and bcc fields are also blank in copies & addressing tab section for office@mydomain.com (original account address). Right now i remove this unnecessary office@mydomain.com from TO field manually each time when i reply any copied email. Let me know, Is it possible to prevent to add original/coping account address (office@mydomain.com) in TO field when reply from another account (xyz@protonmail.com)? Screensorts links are below:- https://drive.google.com/open?id=1txDRCeVu8ejbkWmS66MKYSZQ2O_2M7-l https://drive.google.com/open?id=1O__uaC9VDHaPJGJTustUeKskcgDYmvoV